This scenario requires a combination of record-level and field-level access control. Case Teams are the ideal feature for granting different levels of access (Read-Only vs. Read/Write) to a specific case record for different users. The account manager can be assigned a team role with Read-Only access, while the support engineer gets a role with Read/Write access.

To handle the sensitive PII data, Field-Level Security (FLS) is used. FLS allows administrators to control the visibility and editability of specific fields based on a user's profile or assigned permission sets. The PII field can be made visible to the account manager's profile/permission set and hidden from the support engineer's, thus meeting all requirements precisely.

A. Configure View All for the Case object and field-level security.

View All is an object-level permission granting read access to all case records, which is overly permissive and not as granular as using Case Teams for specific record access.

C. Configure OWD for the Case object and implement Salesforce Shield.

Salesforce Shield Platform Encryption protects data at rest; it does not control field visibility in the user interface. Field-Level Security is the correct tool for hiding a field from users.

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1. Case Teams: Salesforce Help, "Set Up Case Teams."

Section: "Case Team Roles" and "Add a Case Team." The documentation states, "Case teams help groups of people work together to solve cases... When you set up case teams, you can create roles to determine each team member’s level of access to a case, such as Read/Write or Read-Only." This directly supports using Case Teams for differentiated record-level access.

2. Field-Level Security: Salesforce Help, "Field-Level Security."

Section: "Set Field-Level Security for a Single Field on a Profile" or "Set Field Permissions in Permission Sets." The documentation explains, "Field-level security settings let you restrict what fields users can view and edit based on their profiles and permission sets." This confirms FLS is the correct mechanism for controlling visibility of the PII field.

3. Object Permissions: Salesforce Help, "Object Permissions."

Section: "Standard Object Permissions." The documentation clarifies that the "View All" permission on an object allows a user to "View all records associated with this object, regardless of sharing settings." This highlights why option A is incorrect, as it's a broad permission, not a record-specific one.

4. Salesforce Shield: Salesforce Help, "Salesforce Shield."

Section: "Platform Encryption." The documentation specifies, "Shield Platform Encryption gives your data a whole new layer of security while preserving critical platform functionality. It enables you to encrypt sensitive data at rest..." This confirms that Shield's purpose is encryption, not controlling UI visibility, making option C incorrect.