[单选题]
A nuclear reaction is said to be exothermic if es a-zow, hyy* vh:8w0the total kinet rrr8.puarowg/-4 j1lixp p, 5ic energy is
A. less after the reaction than before.
B. equal both before and after the reaction.
C. greater after the reaction than before.
D. zero after the reaction.