According to the law of conservation of energy what ultimatly happens to the total amount of energy in the universe?

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it transforms from one form to another. For instance, chemical energy can be converted to kinetic energy in the explosion of a stick of dynamite.

Ithink the answer is c but then again i'm probably wrong