This Surveillance task is described as watching a specific location to determine the potential for the presence of a CBRN hazard using visual means.

• A. Observe
• B. Monitor
• C. Detect
• D. Quantify

Answer: (A)

Observing is about visually watching a location to pick up signs that a hazard might be present. It captures the act of using sight to gather initial information about potential risk. Monitoring implies ongoing or instrument-assisted surveillance, detecting means confirming that a hazard exists, and quantifying involves measuring how much of something is present. Since the task specifies a visual, one-time-like assessment of a specific spot to gauge potential presence, observing is the best fit.