What safety device is used by the operator to warn others of danger, or signal the spotter?

• A. Horn
• B. Alarm
• C. Light
• D. Bell

Answer: (A)

Audible warning is the key idea here. The operator uses a horn to quickly grab attention and signal the spotter or anyone nearby that danger is present or that movements are about to begin. A horn carries sound over distance and around obstacles, making it reliable on a busy site where people may be spread out or distracted by activity. Visual devices like lights can be missed in bright daylight or from some angles, alarms aren’t standardized for outward signaling, and bells are slower to notice in a noisy environment. So the horn is the most effective, immediate way to warn others or communicate with the spotter.