Energy and Mass Are Equivalent According to Einstein, and Both

Multiple Choice

Energy and mass are equivalent according to Einstein, and both can be measured in electron volts. (1 eV is the energy acquired by an electron when accelerated through 1 volt.) If the rest mass of an electron is 511 keV, what is the threshold energy of a gamma-ray photon in order that it can undergo electron pair production?

A) 1.533 MeV
B) 1.022 MeV
C) 0 eV, because it produces a particle-antiparticle pair
D) 511 keV