5characteristics of an electromagnetic wave

1. Electromagnetic waves travel with a constant velocity in vacuum . The velocity is approximately 186,000 miles per second or 300, 000 km per sec, the same as the speed of light.

2.Electromagnetic waves are not deflected  by electric or magnetic fields

3. Electromagnetic waves can show interference or diffraction

4. Electromagnetic waves are transverse waves, similar to water waves in the ocean or the waves seen on a guitar string. 

5. Electromagnetic waves may be polarized.

6. Electromagnetic waves need no medium  of propagation. 

i think the answer is a, hope this : )

e/c, where e is its total energy