As the wavelength increases, the frequency? A. decreases and energy decreases B. increases and energy increases C. decreases and energy increases D. increases and energy deceases

For the same wave, the product product of

(wavelength) times (frequency)

is always the same number. (It happens to be the speed of the wave.)

So if one of them changes, the other one has to change in the opposite

direction, in order to keep their product constant.

For electromagnetic waves, higher frequency means higher energy.

I'm not sure about mechanical waves just now.