Concept:Communication satellites make it possible to transmit telephone signals across long international distances.
Explanation:Telephone signals from one country cannot easily travel directly to another country using only local wires.
A communication satellite receives signals from a ground station in the caller’s country.
It then amplifies the signals using a transponder.
Finally, it retransmits the signals to another ground station in the receiver’s country.
This process creates a communication channel between a source transmitter and a distant receiver on Earth.
Therefore, the transmission of telephone services between countries is facilitated by communication satellites.
Answer:D. communication satellite