[单选题]
A nuclear reaction is sai(w-qgu0dh0oox xtw ;dl(80tv d3-tkegpa vcb00h6nt +be v0t- to be exothermic if the total kinetic 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.