Which of the Following Statements Regarding Einstein's Equation Relating Mass

Which of the following statements regarding Einstein's equation relating mass and energy is correct?

A) Ordinary chemical change occurs too slowly for the conversion of mass to energy to be observed.
B) The amount of energy available from a nuclear reaction decreases as the change in mass increases.
C) Small changes in mass result in very large changes in energy because of the speed of light squared dependence.
D) The mass of the universe must remain constant even though energy is released during nuclear change.
E) The energy of the universe is decreasing because the mass of the universe is increasing.