Explanation:

Why C is correct:
A change set is the standard declarative tool for migrating configuration from a sandbox to production. When you add a field to a change set, it includes the field's definition and all its associated field-level security (FLS) settings for all profiles. By adding the Amount field and selecting all six custom profiles in the change set, you are packaging the exact FLS configuration (visible/read-only/required for some, hidden for others) that you configured in the sandbox. Deploying this change set will apply the same FLS settings to the profiles in production, ensuring the change is replicated accurately and efficiently.

Why A is incorrect:
You cannot "push" a sandbox template to production. Sandbox templates are used to define the data and configuration of a new sandbox at the time of its creation. They are not a deployment mechanism for moving specific changes from an existing sandbox to production.

Why B is incorrect:
While manually updating the FLS in production via Setup would technically work, it is error-prone, time-consuming, and not a best practice. The question specifies there are six custom profiles, and the change was made to three of them. Manually re-applying these changes introduces a significant risk of human error (e.g., forgetting one profile, misconfiguring the permissions). The entire purpose of a deployment tool like a change set is to automate this process and guarantee consistency between environments.

Why D is incorrect:
This is a misunderstanding of how change sets work. You do not add profiles themselves to a change set to deploy FLS changes. The FLS is a property of the field. You add the field to the change set, and the deployment process reads the FLS settings for that field from the source sandbox and applies them to the target production org. Adding just the profiles would not convey the specific FLS settings for the Amount field.

Reference:
Salesforce Help: Deploy Change Sets - This outlines the process of using change sets.
Salesforce Help: Add Components to a Change Set - Specifically, when you add a field, it includes its "field-level security and field properties."

Explanation:

Warning message: Deselecting the "disable session timeout warning popup" setting ensures users receive a warning message before their session expires due to inactivity.
Preventing unexpected logout: This allows users to extend their session or save their work, preventing them from being logged out unexpectedly.

Why other options are incorrect

B. Select force logout on session timeout: Enabling this setting would cause users to be logged out immediately upon session timeout without any warning, which is the opposite of the desired outcome.
C. Remove the session timeout settings: Removing session timeout entirely is a security risk and is not a recommended practice.
D. Enable Remember me until logout: This option is related to retaining login credentials and not directly to preventing unexpected session timeouts during an active session.

Explanation:

Because the account is owned by a user in the Galaxy Manager role (higher in the hierarchy), users in the Galaxy Subordinate role (lower) do not inherit access to the manager’s records via the role hierarchy—access flows upward, not downward or across.

If only one of the two subordinates can see the account, the typical reason is that the owner (or someone with sufficient rights) manually shared that specific account with that one user. Manual sharing grants record-level access to selected users/roles/groups on a one-off basis, which explains why the other subordinate (same role, same profile) cannot see it.

Not A (Workflow Rule): Workflows don’t grant record access; they automate field updates, emails, tasks, etc.
Not C (Queues): Accounts aren’t owned by queues (queues are for objects like Cases/Leads/custom objects that are queue-enabled).
Not D (Role Hierarchy): Would have given managers access to subordinates’ records, not the other way around.

So the discrepancy arises from Manual Sharing to just one of the sub-role users.

Explanation:

Change sets are the declarative, standard method for migrating metadata (e.g., profile updates, custom apps, page layouts) from a sandbox to production. They ensure dependencies are included and allow validation before full deployment.

To migrate:
Outbound Change Set (C):
In the sandbox, go to Setup > Outbound Change Sets > New. Add components: select "App" for the new app, then "Profile" for the updated profiles (use "View/Add Dependencies" to auto-include related items like permissions or layouts). Upload the change set to production.
Inbound Change Set (D):
In production, go to Setup > Inbound Change Sets, find the uploaded set, validate it first (deploys in test mode to check for errors), then deploy. Monitor via Deployment Status for success.
This workflow is secure, auditable, and supports rollback if needed.

Why Not the Other Options?

A. Package deployment:
Packages (managed/unmanaged) are for distributing apps to external orgs or AppExchange, not internal sandbox-to-production moves—they require packaging and installation steps that add complexity without benefits here.
B. Change Data Capture:
This is an event-driven platform feature for streaming record changes (e.g., to external systems), not for deploying metadata like profiles or apps.

References
Salesforce Help: Create and Upload an Outbound Change Set – Guide for sandbox-side setup.
Salesforce Help: Deploy an Inbound Change Set – Covers validation and deployment in production.
Trailhead Module: Deploy with Change Sets – Practical steps for profile and app migrations.

Explanation:

The core problem is the time it takes to route the case to the correct support agent "by area of expertise according to product information" after submission.

Omni-Channel is the feature designed specifically to route work (like Cases) to the most qualified, available agent based on criteria such as skills, product expertise, and capacity.

The administrator would configure Omni-Channel by:

Defining Service Channels (e.g., Cases).
Creating Routing Configurations to define how cases are prioritized and routed (e.g., based on the Product field on the case).
Assigning agents Skills (e.g., "Sneaker Product Expert," "Boots Product Expert") and linking those skills to the Routing Configuration.
The system then automatically pushes the new case to the agent with the required skills and current capacity, dramatically reducing the time the case spends waiting for manual assignment.

This directly addresses the customer frustration regarding the time delay and the need for skill-based routing.

Why the Other Options are Incorrect

B. Escalation Rules:
These rules are used to move a case to a higher-level support tier or manager if it hasn't been solved within a specific time period (Service Level Agreement violation). They address time-to-resolution, but not the initial, correct-agent-assignment problem.
C. Macros:
Macros are productivity tools that let agents perform common repetitive tasks with a single click (e.g., sending an email, updating case fields). They improve agent efficiency after the case is assigned, but don't handle the assignment/routing process itself.
D. Knowledge Component:
The Knowledge component allows agents (or customers) to search for and attach relevant articles. This is excellent for case deflection or first-call resolution, but it is not a tool for routing a case to a specific agent.