The oxidation states shown by Mn in the given reaction are : 2...

In $\mathrm{MnO}_4^{-}$, let the oxidation state of Mn be $x$.

$x + 4(-2) = -1 \Rightarrow x = +7$

In $\mathrm{Mn}^{2+}$, the oxidation state of Mn is $+2$.

In $\mathrm{MnO}_2$, let the oxidation state of Mn be $y$.

$y + 2(-2) = 0 \Rightarrow y = +4$

The oxidation states shown by Mn in the given reaction are $+7$, $+2$, and $+4$.

These correspond to D, E, and B respectively.

Answer: B, D and E only