Which of the following arc consistent with the conservation of mass?

A. CO+1/2 O2 —->CO2

B. ZnSO4 + Li2CO3—-> 2 CO2 + 2 H2O

C. C2H4O2 + 2 O2—> 2 CO2 + 2 H2O

D. 3 AgBr+ GaPO4——> Ag3PO4 + GaBr3