The wavelength is the length that it takes a wave to complete one cycle (measured between any two peaks or troughs that are next to each other).
More energetic light has a SHORTER wavelength, so that's not what we want.
But frequency is a measure of how long it takes for a wave to complete one cycle, or how many wavelengths pass in a certain time. We usually use one second, so the unit is [tex]s^{-1}=Hz[/tex].
Logically, shorter wavelength means that more waves pass in a second. (We deduce that frequency and wavelength are inversely proportional.)
So, more energy = shorter wavelength = greater frequency, so the answer is B.
