A positron is a particle similar to an electron, but with the opposite charge of an electron. If a positron and an electron collide, sometimes both the electron and positron disappear (annihilate), and two photons are created. This is an example of .A. the conversion of potential energy into thermal energyB. the conversion of rest-mass energy into radiative energyC. the conversion of rest-mass energy into kinetic energyD. the conversion of kinetic energy into rest-mass energy