Field-Level Security (FLS) controls whether a user can see, edit, and delete the value for a particular field on an object. This is managed through Profiles and Permission Sets. The administrator should configure the sales reps' profile to have 'Visible' access to the 'Profit' field and the partner consultants' profile to have 'Hidden' access. Alternatively, a permission set granting visibility to the field could be created and assigned only to the sales reps, providing a more granular and additive approach to permissions.

B. Record types control page layouts and picklist values. Hiding a field on a page layout does not prevent access via reports or the API.

C. Organization-Wide Defaults (OWDs) control record-level access (which records a user can see), not field-level access (which fields they can see).

1. Salesforce Help. (2024). Set Field-Level Security for a Single Field on All Profiles. "Field-level security settings let you restrict what fields users can view and edit based on their profile."

2. Salesforce Help. (2024). Permission Sets. "You can also use permission sets to grant access to... field-level security."

3. Trailhead. (2024). Data Security Module, Control Access to Fields Unit. "You can control the visibility of fields in any part of the app, including... reports... You can set field-level security through profiles or permission sets."