In which of the following reactions, H₂O₂ acts as reducing agent?
A. Cl₂+H₂O₂→2HCl+O₂
B. H₂O₂+O₃→H₂O+2O₂
C. HCHO+H₂O₂→HCOOH+H₂O
D. PbO₂+H₂O₂→PbO+H₂O+O₂