Which technique uses detectors throughout a geographic area?

• A. Area Array uses detectors throughout a geographic area.
• B. Critical Node uses detectors around a high-value target.
• C. Monitor means checking the environment passively.
• D. Observe means watching a location visually.

Answer: (A)

The idea is wide-area surveillance achieved with detectors spread across a geographic region. Deploying detectors throughout the area creates broad coverage, so signals from events anywhere within that space can be detected and, if needed, triangulated or correlated for localization. This contrasts with focusing sensors around a single target, which limits visibility to a small zone and misses activity elsewhere. Passive monitoring describes checking the environment but doesn’t specify how sensors are distributed over a large area, and simply observing a location involves human visual attention rather than an engineered, distributed detector network. So the approach that uses detectors across the entire geographic area best fits the question.