Suppose frequency of emitted photon is `f_(0)` when the electron of a stationary hydrogen atom jumps from a higher state `m` to a lower state `n`. If the atom is moving with a velocity `v(lt lt c)` and emits a photon of frequency `f` during the same transition,then which of the following statement are possible?

Options

A. f may be equal to `f_(0)`
B. f may be greater than `f_(0)`
C. f may be less than `f_(0)`
D. f cannot be equal to `f_(0)`