[单选题]
How does the mass of the produ0 eqtst9a0tx *,jz(v f0c j+jsc+0dj)x (a4eg ghqlau k0ot2:gts of a nuclear fusion reaction compare to the mass of the o2 jk q(aht de0) +u0gagg:lx4original elements?
A. greater
B. less
C. the same
D. varies according to the reaction
