Basic Concept: This question tests database auditing and query visibility. DP-300 expects you to distinguish between collecting audit events, retaining logs, and analyzing query behavior.
Why A is Correct: Apply a sensitivity label to each column. is correct because it is the feature whose normal purpose matches the stated requirement. Apply a sensitivity label to each column. is a security-related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. The scenario wording points to that specific behavior: You need to recommend a data classification strategy for Customers.
Why B is Wrong: Transparent Data Encryption protects database files, backups, and logs at rest; it does not encrypt data in use or enforce user-level data visibility. It does not satisfy the required identity, encryption, firewall, auditing, or data-exposure boundary described in the scenario: You need to recommend a data classification strategy for Customers.
Why C is Wrong: Dynamic Data Masking obscures sensitive values in query results for non-privileged users, but it does not restrict which rows are returned. It protects or manages a different security layer, so the required database access or protection behavior would still be incomplete.
Why D is Wrong: Apply a sensitivity label to Customers is a security-related control, but its value depends on whether the requirement is identity, encryption, auditing, network isolation, or data exposure reduction. It is not the right enforcement point for this case; the scenario needs the control that governs the data or identity path being tested.