#### Answer

Choice D.

#### Work Step by Step

Photon emission means that the electron falls from a higher-n state to a lower-n state.
Energy levels are more closely spaced for higher values of n. The transition from 8 to 5 emits a photon with lower energy than the photon emitted by a n=5 to n=2 transition. This lower energy means a smaller frequency and a longer wavelength.