同温同压下，当反应物分解了8%时，总体积也增加8%的是(    )

A．2NH3(g)====N2(g)+3H2(g)	B．2NO(g) ====N2(g)+O2(g)
C．2N2O3(g) ====4NO2(g)+O2(g)	D．2NO2(g) ====2NO(g)+O2(g)