Explanation:

To identify and address security risks in a Salesforce org — especially those related to custom apps and Lightning Web Components (LWCs) — the Health Check tool is the most appropriate choice.

🔹 Why Option A Is Correct:
Health Check evaluates your org’s security settings against Salesforce’s recommended baseline.
It helps uncover vulnerabilities such as:
Weak password policies
Insecure session settings
Unrestricted IP ranges
While it doesn’t scan LWCs directly, it ensures the org-level security posture is strong enough to support secure component behavior.

❌ Why the Other Options Are Incorrect:

B. Master Encryption Keys
Used for Shield Platform Encryption, not for detecting security risks.
Doesn’t analyze or expose vulnerabilities in LWCs.

C. Salesforce Optimizer
Focuses on performance and usage insights (e.g., unused fields, page layouts).
Not designed to detect security risks in components or org settings.

D. Self-signed Certificates
Used for authentication and secure communication, not for security auditing.
Doesn’t help expose risks in Lightning components.

🔗 Reference:
Health Check Overview
Secure Coding for LWCs

Explanation:

Multi-Factor Authentication (MFA) requires a user to provide two or more distinct forms of verification to prove their identity. These factors are typically categorized as:

Something you know (e.g., a password or PIN).
Something you have (e.g., a physical device or an app on your phone).
Something you are (e.g., a fingerprint or facial recognition).

Let's analyze the options:

A. An Authentication App (Correct)
This represents the "something you have" factor. An authentication app (like Salesforce Authenticator, Google Authenticator, or Microsoft Authenticator) generates a time-based, one-time password (TOTP) that is tied to the user's specific device. This is a standard and highly recommended method for the second factor in MFA.

B. A Username and Password (Correct)
The username and password combination represents the "something you know" factor. This is the first, foundational layer of authentication. MFA builds upon this by requiring a second, different type of factor.

C. A Security Token (Incorrect)
A security token is a long, case-sensitive alphanumeric code that is appended to a user's password when logging in via the API or from an untrusted network. It is a form of two-factor authentication, but it is not the same as the modern, user-friendly MFA that Salesforce recommends and promotes. Salesforce is moving towards phasing out security tokens in favor of verification codes from authenticator apps.

D. An Encryption Key (Incorrect)
An encryption key is used to encrypt and decrypt data at rest. It is a tool for data security, not for user authentication. It is not a factor used in the MFA process.

Reference:
Multi-Factor Authentication (MFA): A security enhancement that requires two or more verification factors to gain access to a resource. In the context of Salesforce login, this is typically a password ("something you know") and a verification code from an authenticator app or a built-in authenticator ("something you have").
Salesforce Authenticator: The recommended and most integrated method for implementing MFA in Salesforce. It provides a push notification approval for a seamless user experience.

Explanation:

Why this is right:
You need background automation that fires when an Opportunity is created and then updates the related Account (set Opportunity_Created__c = TRUE). A record-triggered Flow on Opportunity (after create) can look up the parent AccountId and update that Account field—no user clicks, no code, and it works with the standard lookup relationship from Opportunity → Account.

Why not the others:
A. Screen flow — Requires user interaction; it won’t auto-run when an Opportunity is created.
B. Workflow rule — Cross-object field updates from a child to a parent don’t work for lookup relationships like Opportunity → Account (they work for master-detail). So a workflow on Opportunity can’t update the Account checkbox.
D. Assignment rule — Only applies to Leads and Cases for ownership/routing, not Account field updates.

Build it fast (recommended pattern):
Record-Triggered Flow on Opportunity, when a record is created (After Save).
Update Records → choose “Specify conditions to identify records, and set fields individually” → Record to update: the related Account where Id = $Record.AccountId.
Set Opportunity_Created__c = TRUE.
(Optional) If you want to uncheck it when there are no open Opportunities left, add an additional after-save flow on Opportunity for delete/update that counts related Opps and unchecks when count = 0.

Explanation:

The goal is to grant a small, specific group of users the ability to View All Data across the organization for compliance purposes, regardless of their standard profiles and roles. Using a Permission Set is the most flexible, secure, and modern approach to meet this requirement.

Permission Set
A Permission Set is a collection of settings and permissions that extend a user's functional access without changing their profile.
Configuration: The administrator can create a new Permission Set (e.g., "Compliance Data Access") and enable the "View All Data" system permission within it.
Assignment: The Permission Set is then assigned only to the small subset of users who require this specific, high-level access.
Benefit: This approach follows the Principle of Least Privilege, ensuring that these users retain their existing profiles and roles for their day-to-day work, while only gaining the special "View All Data" permission where necessary. It's easy to audit and revoke the permission instantly by removing the Permission Set assignment.

Why the Other Options are Incorrect

A. Assign delegated administrator to the subset of users to View All Data:
Delegated Administration is designed to allow a user to manage user creation, reset passwords, and manage specific custom objects. It does not automatically grant "View All Data" across all standard and custom objects.

B. Create a new profile and role for the subset of users with the View All Data permission:
Creating a new Profile is often unnecessary and overly complex for granting a single, specific permission. If these users already have roles and profiles that govern their other access (like Object and Field Permissions), moving them to a new Profile could inadvertently change or break their existing, necessary access. Permission Sets are designed specifically to layer permissions on top of existing profiles.

C. Enable the View All Data permission for the roles of the subset of users:
Permissions are not assigned to Roles. Permissions are assigned through Profiles and Permission Sets. Roles primarily manage the record visibility hierarchy (for sharing rules and Organization-Wide Defaults). Therefore, this option is technically impossible to configure in Salesforce.

Explanation:

The requirement is to display a count of related child records (Open Houses) that meet a specific criteria (Status = 'Pending') directly on the parent record (Property). This is the exact purpose of a Roll-Up Summary Field.

Let's analyze the options:

A. Lightning Component (Incorrect)
While a custom Lightning Component could be built to perform this calculation, it would be a complex, custom-coded solution for a problem that has a simple, declarative, and standard solution. This is over-engineering and not the recommended approach.

B. Formula Fields (Incorrect)
A formula field on the parent Property object cannot perform a COUNT operation on its child Open House records. Formula fields are powerful for calculations based on fields on the same record or from a single parent record, but they cannot perform aggregate functions like counting related records.

C. Roll-Up Summary (Correct)
A Roll-Up Summary Field is a native Salesforce field type available on the parent object in a master-detail relationship. It is designed specifically for this use case. The administrator can create a Roll-Up Summary field on the Property object with the following configuration:
Summarized Object: Open House
Filter Criteria: Status EQUALS Pending
Roll-Up Type: COUNT()
This field will automatically and dynamically count the number of related "Pending" Open Houses and display the value directly on the Property page layout.

D. Visualforce Page (Incorrect)
Like a Lightning Component, a Visualforce page is a custom, code-based solution. It is an outdated technology (compared to Lightning) and is unnecessary for this straightforward declarative requirement. It would require Apex code to perform the query and count.

Key Concept:
Roll-Up Summary Field (RSF): A field on a master record that automatically calculates the SUM, COUNT, MIN, or MAX of values in related detail records. It is the standard, declarative way to display aggregated data from a child object on its parent.
Prerequisite for RSF: A Roll-Up Summary Field requires a Master-Detail or Lookup relationship (with certain configurations for Lookup) between the objects. The question specifies a Master-Detail relationship, which is perfect for this solution.