12) Consider five beams of photons striking a metal surface in a photoelectric effect experiment. If only one beam is capable of ejecting electrons from the surface of a metal, which beam is it?
Beam of photons with the frequency of _____.
A) $1 \times 10^{14} s^{-1}$
B) $5 \times 10^{14} s^{-1}$
C) $1 \times 10^{15} s^{-1}$
D) $5 \times 10^{15} s^{-1}$
E) $1 \times 10^{16} s^{-1}$