Which statement best describes a perimeter intrusion detection system's function?

• A. They generate an alert when intrusions detected by sensors
• B. They automatically shut down runways
• C. They produce weather forecasts
• D. They replace human guards entirely

Answer: (A)

Perimeter intrusion detection systems detect unauthorized boundary breaches and notify security personnel. They use sensors such as motion detectors, fiber optic sensors, or cameras, and when intrusion is detected they generate an alert to trigger a response. This alerting capability is what makes the system effective: it informs operators so they can investigate and respond. It does not automatically shut down runways, produce weather forecasts, or replace human guards entirely; those are outside the system’s role. The value lies in timely notifications that support rapid, coordinated security actions.