Answer:
C. either A or B
Explanation:
To calculate the energy of a photon returning to its ground state, we required either the frequency or the wavelength. Often times, not both.
The wavelength of a photon can be derived by;
E = hf
or
E = [tex]\frac{hc}{wavelength}[/tex]
h is the Planck's constant
c is the speed of light
f is the frequency