The correct option is A H2O2→2H−+O2+2e−
H2O2 should get oxidised as it acts as a reducing agent. Hence, O2 should formed as one of the products of this half reaction (as it would then be an oxidation half reaction as oxygen gets oxidised from −1 to 0). Therefore, the reaction is: H2O2→2H−+O2+2e−.