Energy is a form of energy caused by the vibration of matter within a solid, liquid, or gas.

a. light
b. sound
c. chemical

B

Explanation:

Sound energy is caused by vibrations. Think of a speaker. An electromagnet changes it's current very quickly, due to electrons moving up and down within the attenna. This, the electromagnet is always changing poles. A magnet is inside the electromagnet coil, and attracts/repels from both sides due to the sudden changes. Thus, the magnet vibrates, letting off sound waves.

This is how you can also make a radio with only a coil of wire (electromagnet) and a permanent magnet, along with a larger object to amplify the sound.