$\left(\mathrm{a}\right) {\mathrm{H}}_2{\mathrm{O}}_2+{\mathrm{O}}_3\to {\mathrm{H}}_2\mathrm{O}+2{\mathrm{O}}_2$
${\left(\mathrm{b}\right)\mathrm{ }\mathrm{H}}_2{\mathrm{O}}_2+\mathrm{A}{\mathrm{g}}_2\mathrm{O}\to 2\mathrm{A}\mathrm{g}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$
Role of hydrogen peroxide in the above reactions is respectively:

• A

  Oxidizing in $\left(\mathrm{a}\right)$ and reducing in $\left(\mathrm{b}\right)$
• B

  reducing in $\left(\mathrm{a}\right)$ and oxidizing in $\left(\mathrm{b}\right)$
• Correct answer
  C

  reducing in $\left(\mathrm{a}\right)$ and $\left(\mathrm{b}\right)$
• D

  oxidizing in $\left(\mathrm{a}\right)$ and $\left(\mathrm{b}\right)$

Hence, the correct answer is option: 'C'.