What describe the Einsteins equation for the relativity of mass and energy ?

The correct option is C a small amount of mass contains a lot of energy.
Sir Einstein's mass-energy equation states that mass and energy can be converted into each other by the following relation.

$E=m{c}^2$, ($c=$speed of light)

This implies that a small amount of mass contains a lot of energy, which can be proved with an example.

Let we have a mass of $1g={10}^{-3}kg$ , therefore energy produced by it will be:

$E={10}^{-3}\times {(3\times {10}^8)}^2=9\times {10}^{13}J$

which is a vast amount energy produced by only one gram (small mass) of mass.

Whereas a small amount of energy doesn't give a large amount of mass because for that we have to divide the energy by $c^2$, which gives a small mass.