The first documented form of police communication was a bell.

• A. A whistle
• B. A horn
• C. A flag
• D. A bell

Answer: (C)

Visual signals using a flag show how police could coordinate actions over a distance with a simple, observable cue. A flag can be raised or displayed so everyone nearby sees the same signal at the same time, making it reliable for directing multiple officers in streets, crowds, or from different positions. This kind of signaling is more adaptable than sound-based signals because it conveys specific messages through established visual codes and works in noisy environments or when officers are spread out.

A bell, while effective to grab attention, doesn’t carry distinct instructions or orders, so it’s less versatile for directing actions. A whistle or horn produces sound that can be heard only by those nearby and can be drowned out by noise, making precise communication harder. The flag offers a clear, codified means of signaling, which is why it’s considered the best answer here.