When an electron of an atom returns from an excited state to the ground state, it emits energy in the form of a photon. How does the change in energy level compare to the energy of the emitted photon?

AIt is less than the energy of the photon.

BIt is about one third the energy of the photon.

CIt is exactly half of the energy of the photon.

DIt is equal to the energy of the photon.

EIt is exactly twice the energy of the photon.