[单选题]
A nuclear reaction is sa8 zky4a f8rf+7 nzyzz3id to be exothermic if the total kinetic energyjv6q(akhb s,i4bc dd26e4f * f 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.