A student is instructed to design a device that can allow one user to hear the voice of another user at a distance of 5 kilometers. Which statement describes the MOST applicable basic design concept?
O A A device designed to create a strong magnetic field should be developed
O B. A device designed to turn an electric current into heat should be developed
OC. A device designed to produce waves with large amplitudes should be developed.
O D. A device designed to transmit electromagnetic waves through the air should be developed