We recall that the energy of the electron at rest is 0.511 MeV and let c be the speed of light. The energy required to accelerate an electron from an initial speed of 0.500c to a final speed of 0.900c is *

A. 2.45 MeV

B. 0.511 MeV

C. 0.582 MeV

D. 938 MeV