Which of the following is an example of a detective security measure?

• A. Access control systems at entry points.
• B. Physical barriers like fences.
• C. CCTV cameras and security alarms.
• D. Employee background checks.

Answer: (C)

Detective security measures are those that reveal or detect security events as they happen or after they occur, so they enable a response and provide evidence. CCTV cameras and security alarms fit this role because they actively monitor and record activity and trigger alerts when something out of the ordinary happens. This real-time observation allows security staff to respond quickly and gives investigators a clear trail of what occurred.

Other options focus on preventing entry or pre-screening people rather than detecting events. Access control and physical barriers aim to stop unauthorized access before it happens, while background checks aim to reduce risk by screening personnel beforehand. CCTV and alarms, by contrast, are about detecting and signaling an incident as it occurs or after, making them classic detective controls.