Summary:
This question tests the interaction between object permissions, Organization-Wide Defaults (OWD), and the "Controlled by Parent" setting. Service reps have "View All" on Case, granting them object-level access to all case records. The key is understanding how this grants them access to parent Account and Contact records through implicit sharing, which is only possible if the Contact OWD is set to "Controlled by Parent."

Correct Option:

C. Service reps will be able to access the relevant Contacts if their OWD is Controlled by Parent.
This is the correct and critical detail. When a service rep accesses a Case (which they can do because of "View All"), Salesforce implicitly grants them read-only access to the parent Account. If the Contact OWD is "Controlled by Parent," this implicit read access to the Account cascades down to the Contacts associated with that Account. This gives the rep a complete view of the customer.

Incorrect Options:

A. Service reps will NOT be able to access the relevant Accounts if their OWD is Private.
This is incorrect. Due to implicit sharing, when a user has access to a child record (the Case), they are automatically granted read-only access to the parent record (the Account), even if the Account OWD is Private. The "View All" on Case is what triggers this implicit share to the parent Account.

B. Service reps will NOT be able to access the relevant Contacts if their OWD is Controlled by Parent.
This statement is the direct opposite of the correct answer. If the Contact OWD is "Controlled by Parent," and the service rep has implicit read access to the parent Account (from the Case), then they will be able to access the relevant Contacts. This is the intended behavior of the "Controlled by Parent" setting.

Reference:
Salesforce Help: Implicit Sharing

Summary:
The requirement is to restrict the visibility of a specific field (VIP Flag) on the Contact object to only users with the "Private Banking Rep" profile. This is a classic field-level security (FLS) requirement. The solution must control whether the field is rendered on the page at all for a given user, which is a function of the user's profile and permission sets, not the page layout.

Correct Option:

C. Set the Field Level Security for the VIP Flag field so that it is visible to Private Banking Rep Profile.
This is the correct and foundational approach. Field-Level Security in the profile is the primary gatekeeper that determines if a field is visible, readable, or editable. By setting the FLS for the VIP Flag field to "Visible" only for the Private Banking Rep profile and "Not Visible" for all other profiles, the field will be hidden from users who should not see it, regardless of the page layout they are assigned.

Incorrect Options:

A. Change the type of VIP Flag field to a picklist, define a new record type for the Contact Object and make the picklist field available for Editing.
This is an overly complex and incorrect solution. Record types control which fields are available on a page layout for a specific category of records, not which users can see a field. A user with a profile that has FLS access to the field could still see it on a different record's layout or via the API. It does not securely hide the field based on user role.

B. Define a page layout for Contact Object and add the VIP Flag field for that layout.
Remove the VIP Flag field from other layouts. This is insecure and incorrect. Page layouts only organize fields that a user already has permission to see via their profile. If a user's profile has FLS granting them visibility to the VIP Flag field, they can still access it via reports, the API, or by switching to a different layout (if available), making this an unreliable method for enforcing security.

Reference:
Salesforce Help: Field-Level Security

Summary:
A "Private Library" in Salesforce Files is a personal storage area for a single user. By its name and design, it is intended to be completely isolated from the rest of the organization's data and users. The sharing and visibility rules that apply to records (like role hierarchy or object permissions) do not apply to the contents of a user's private library.

Correct Option:

C. Only the user.
This is the correct and defining characteristic of a Private Library. Content stored here is accessible only by the user who owns the library. Not even system administrators can view these files through the standard Salesforce interface unless they log in as that specific user. It is the most restrictive and personal storage location for files.

Incorrect Options:

A. The user and users above them in the Role Hierarchy.
The role hierarchy governs record-level data access (e.g., who can see an Account or an Opportunity). It does not grant access to personal files stored in a user's private library. File library access is a separate security model.

B. The user and users with View All Data permission.
The "View All Data" permission is a powerful system-wide permission that overrides sharing rules for records in the database. However, it does not grant access to the content within a user's private file library. The privacy of this library is enforced independently of object-level data permissions.

Reference:
Salesforce Help: Libraries and Sharing Model

Summary:
The "Site User" is the internal user record that represents and authenticates an external community user. The "Site User Visibility" setting controls whether these internal Site User records are visible to other community members. When this setting is turned off, it primarily impacts the social and collaborative features within the community that rely on being able to see and interact with other members.

Correct Option:

B. Searching for other external users.
This is the function that is directly impacted. When "Site User Visibility" is disabled, external community users cannot see the list of other community members. This means the "People" tab and search functionality for finding other external users within the community will not work, as the underlying Site User records are hidden. It prevents users from networking or collaborating with each other.

Incorrect Options:

A. Updating their user profile.
A user's ability to edit their own profile information in the community is controlled by the "Manage External Users" permission and the specific page layouts for the community profile, not by the Site User Visibility setting. Turning this off does not prevent a user from updating their own details.

C. Searching for internal users.
This setting specifically controls the visibility of external community users (Site Users). It does not govern whether external users can see internal users. The visibility of internal users to the community is controlled by other factors, such as sharing rules and the "Manage Internal Users" permission.

Reference:
Salesforce Help: Control the Visibility of Experience Cloud Users

Summary:
The issue is a field-level visibility problem, not a record-level access problem. The fact that sales users can see the record in search results and can view a minimal detail page confirms they have object-level "Read" permission and record-level access. The discrepancy between what the admin sees and what the sales user sees on the same record points directly to a configuration that controls which fields are displayed, which is dependent on the user's profile.

Correct Option:

B. The Sales Users profile does not have access to the remaining fields.
This is the most likely cause. Field-Level Security (FLS) in the user's profile determines whether a field is visible (Read permission) and/or editable (Edit permission). If the sales profile lacks "Read" access to most fields on the Invoice object, those fields will be hidden from them on all pages, including the record detail page, regardless of the page layout. The admin, who typically has "View All Data," bypasses these restrictions.

Incorrect Options:

A. A role-based sharing rule is missing and should be added for the sales user's role to grant access to the fields.
Sharing rules control record-level access (which records a user can see), not field-level access (which fields on a record a user can see). Since the sales user can see the record itself, a sharing rule is not the issue

C. The page layout assigned to Sales User profile has only Read-Only access to the fields.
Page layouts control the organization of fields on a page and can set them to read-only, but they cannot hide fields that have been granted FLS "Read" access. If a field is missing entirely from the page, the first place to check is the Field-Level Security for the profile, not the page layout. The layout is secondary to FLS.

Reference:
Salesforce Help: How Field-Level Security and Page Layouts Work Together