What happens to a low-frequency photon when it hits a metal plate if its energy is less than the work function Wo?
 A
 An electron is emitted that has higher energy than the incident photon.
 B. An electron is emitted from the metal surface.
 C
 An electron is emitted from the metal surface but is immediately reabsorbed.
 D.
 An electron is not emitted from the metal surface.