When an Electron De-Excites from the Third Quantum Level to the Second

Multiple Choice

When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. The sum of the emitted frequencies equals the frequency of the single photon that would be emitted if de-excitation were from the third to

A) the second level.
B) the ground state.
C) any other level.
D) none of the above