Answer:
D. It decreases.
Explanation:
As the frequency of a wave on the electromagnetic spectrum decreases the energy of the wave also decreases.
Wave energy and frequency are directly proportional to one another.
 Energy of an electromagnetic wave is given as:
 Energy  = h f
 where h is the plank's constant
       f is the frequency
We see that energy is proportional to frequency. As you go down the electromagnetic spectrum, the amount of wave energy begins to diminish.
