Which of these are electromagnetic waves?
a. light and radio waves
b. sound waves
c. ocean waves and earthquake vibrations

A. light and radio waves

Light is also known as electromagnetic waves. This is because light is actually both an electric and magnetic field. Though it does not seem like it, light does not contain a charge but rather an oscillating field. You can see this happening in your TV. There is no isolated magnetic charge for electromagnetic waves, so you won't be able to do something like put a magnet on the waves.