The speed of a mechanical wave depends on the mechanical properties
of the medium through which the wave is traveling.
The speed of an electromagnetic wave depends on the electrical properties
of the medium through which the wave is traveling.
It's pretty well unanimous for choice <em>A</em> .
Answer:
A microchip in the phone modulates (or varies) a radio wave using the electrical signal. The radio wave travels through the air to a nearby cell tower; the tower sends your voice to the person you are calling and the process is reversed so that the person on the other end can hear your voice.
Please Mark Brainliest If This Helped!