In which of these does H₂O₂ acts as oxidizing agent ?

• A

  ${\mathrm{Mn}}^{+2}+{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{aq}\right)$ in basic medium

• B

  $\mathrm{PbS}\left(\mathrm{s}\right)+4{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{aq}\right)$

• C

  $\mathrm{HOCl}+{\mathrm{H}}_2{\mathrm{O}}_2$

• D

  Both 1 and 2