$\mathrm{M}\mathrm{n}{\mathrm{O}}_4^{-}$ is a good oxidising agent in different media where it changes to
$\to \mathrm{M}{\mathrm{n}}^{2+}$
$\to \mathrm{M}\mathrm{n}{\mathrm{O}}_4^{2-}$
$\to \mathrm{M}\mathrm{n}{\mathrm{O}}_2$
$\to \mathrm{M}{\mathrm{n}}_2{\mathrm{O}}_3$
The oxidation number of Mn correspondingly reduces by

• A

  $-1,-3,-4,-5$
• B

  $-5,-4,-3,-2$
• Correct answer
  C

  $-5,-1,-3,-4$
• D

  $-2,-6,-4,-3$

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