A Validation Rule is the only way to enforce conditional requirement logic based on both record data (the stage) and user data (the user's profile or role). To achieve this, the Platform Administrator would write a formula that checks three things: if the Stage is 'Negotiation,' if the Amount field is blank, and if the user is not a manager. The formula would look something like: AND(ISPICKVAL(StageName, 'Negotiation'), ISBLANK(Amount), $Profile.Name <> 'Sales Manager'). This allows the system to block standard sales users from saving the record without an amount, while the exception for the manager's profile allows them to bypass the requirement. Making the field required on the page layout (Option A) would affect all users equally, failing to meet the requirement for managers. Assigning the Admin profile to managers (Option B) is a major security risk and violates the principle of least privilege.1