Which one of the following reactions indicates the reducing ability of hydrogen peroxide in basic medium?
\( \mathrm{HOCl} + \mathrm{H_2O_2} \rightarrow \mathrm{H_3O^+} + \mathrm{Cl^-} + \mathrm{O_2} \)
\( \mathrm{PbS} + 4\mathrm{H_2O_2} \rightarrow \mathrm{PbSO_4} + 4\mathrm{H_2O} \)
\( 2\mathrm{MnO_4^-} + 3\mathrm{H_2O_2} \rightarrow 2\mathrm{MnO_2} + 3\mathrm{O_2} + 2\mathrm{H_2O} + 2\mathrm{OH^-} \)
\( \mathrm{Mn^{2+}} + \mathrm{H_2O_2} \rightarrow \mathrm{Mn^{4+}} + 2\mathrm{OH^-} \)