An Electron and a Positron,which Are Two Massive Particles,can Annihilate

Multiple Choice

An electron and a positron,which are two massive particles,can annihilate when they come together to produce two photons,which have no mass.This pair annihilation is an example of

A) time dilation.
B) length contraction.
C) the equivalence of mass and energy.
D) the principle of relativity.
E) none of the above.