Which of the following is listed as an odor MWDs are trained on?

• A. Chalk
• B. Ammonium nitrate
• C. Water
• D. Sand

Answer: (B)

MWDs are trained to detect odors that indicate explosives, not everyday or inert substances. Ammonium nitrate is a widely known explosive precursor used in many devices, so its odor is included in training to help dogs recognize a broad range of explosive formulations. The other options—chalk, water, and sand—do not carry explosive odors and aren’t targeted in this kind of training, though they might appear in drills as neutral background. The dog learns to alert when it detects the odor of ammonium nitrate, and the handler reinforces that alert to establish reliable detection in real-world security scenarios.