[单选题]
A nuclear reaction is said to be endothermic if t4vg.fa) ls 8 xxcnw16ohe total k) ll9+oot6w 8z7w6 8t)/js uhoxfxtmminetic 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.