If the Chemical Reaction a + B → C Is

If the chemical reaction A + B → C is exothermic, then which of the following is true?

A) The reaction  C → A + B is exothermic.
B) The reaction  C → A + B is endothermic.
C) The product  C must be a gas.
D) The product  C cannot be a gas.
E) The reactant A must be a solid.