How Is the 'Rest Mass' of an Object Related to Its

How is the 'rest mass' of an object related to its energy?

A) The object's velocity is equal to the speed of light times the rest mass divided by the Lorentz number.
B) The object's rest mass is equal to the gravitational constant times the object's rest mass times the speed of light squared.
C) The object's rest energy is equal to the object's rest mass multiplied by the gravitational constant.
D) The object's rest mass is equal to the object's rest energy multiplied by the speed of light squared.
E) The object's rest energy is equal to the object's rest mass multiplied by the speed of light squared.