In Compton Scattering, a Photon of Wavelength λ and Frequency

In Compton scattering, a photon of wavelength λ and frequency f is scattered from an electron, initially at rest. In this process,

A) the electron gains energy from the photon so that the scattered photon's wave length is less than λ.
B) the electron gives energy to the scattered photon so the photon's frequency is greater than f.
C) momentum is not conserved, but energy is conserved.
D) the photon loses energy so that the scattered photon has a frequency less than f.