Which surveillance technique consists of frequent checks of the environment for the arrival or presence of CBRN hazards?

• A. Continuous
• B. Area Array
• C. Critical Node
• D. Periodic

Answer: (D)

Cadence of surveillance for CBRN hazards is what’s being tested. When the environment is checked at regular intervals to detect the arrival or presence of hazards, that pattern is periodic surveillance. ItRepeat checks over time, offering a balance between timely detection and resource use because it’s not continuous monitoring but occurs on a defined schedule. Continuous monitoring would be nonstop, which isn’t what “frequent checks” describes. Area array refers to how sensors are laid out to cover an area, not how often checks occur, and critical node focuses on monitoring at key locations rather than cadence. So periodic surveillance best fits the idea of repeated, scheduled checks to spot any new hazards.