Which protection approach is designed to detect an intruder before entry is gained?

• A. Perimeter and interior protection
• B. Expanded protection
• C. Sound detection only
• D. False alarm protection

Answer: (A)

Detecting an intruder before entry is gained relies on sensors placed on the outside boundary of the protected area—doors, windows, and exterior zones—so you get an alert before anyone steps inside. This boundary monitoring is perimeter protection, which is designed to deter and detect unauthorized access at the point of entry itself. The option that reflects this approach mentions protection around the exterior (often alongside interior sensors), capturing the idea that you want early warning at the boundary. The other choices don’t focus on pre-entry detection: expanded protection is unclear, sound detection only depends on noise after intrusion, and false alarm protection is about reducing nuisance alarms rather than preventing entry.