单项选择题

A.T0=(T11+T21+T31+T41+T51
B.T0=(T11+T21+T31+T41+T51)/5
C.T0=(T12-T11)+(T22-T21)+(T32-T31)+(T42-T41)+(T52-T51
D.T0=[(T12-T11)+(T22-T21)+(T32-T31)+(T42-T41)+(T52-T51)]/5