-rays radiation can be used to create electron-positron pair. In this process of pair production, -rays energy cannot be less than
(a) 5.0 MeV (b) 4.02 MeV
(c) 15.0 MeV (d) 1.02 MeV
(d) Energy released by -rays for pair production must be greater than 1.02 MeV.