Suppose You Were to Try to Create a Proton-Antiproton Pair

Multiple Choice

Suppose you were to try to create a proton-antiproton pair by annihilation of two very high-energy gamma rays of the same wavelength heading toward each other.The proton and the anti-proton have the same masses,but opposite charges.What would be the minimum energy needed for each photon? (e = 1.60 × 10^-19 C,m_proton = 1.67 × 10^-27 kg,

A) 1.022 MeV
B) 12.2 MeV
C) 1880 MeV
D) 939 MeV
E) 223 MeV