What device extends the range of a radio signal over a larger geographical area?

A repeater is the correct response because it is specifically designed to receive a weak radio signal, amplify it, and then retransmit it. This process allows the radio signal to cover a larger geographical area than it would be able to do so on its own. By taking the original signal and boosting its strength, a repeater can bridge the gaps in coverage that exist due to distance, obstacles, or interference, thus ensuring better communication across greater distances.

Transmitter, amplifier, and receiver each serve significant roles in the communication process as well, but they do not specifically extend the range in the same way. A transmitter sends out the radio signal but does not enhance its reach after the initial broadcast. An amplifier increases the power level of a signal, but on its own, it does not function as a device to receive and retransmit signals to extend coverage. A receiver captures signals but does not enhance or retransmit them; it simply converts the received signals into a usable form for the end user.