$\begin{array}{l}\mathrm{A}) 2{\mathrm{KMnO}}_4\stackrel{ }{\to }{\mathrm{K}}_2{\mathrm{MnO}}_4+{\mathrm{MnO}}_2+{\mathrm{O}}_2\\ \mathrm{B}) 2{\mathrm{NaNO}}_3\stackrel{ }{\to }2{\mathrm{NaNO}}_2+{\mathrm{O}}_2\end{array}$

Correct statement regarding the above reactions is

$\mathrm{A}) 2\mathrm{K}\stackrel{+7}{\mathrm{Mn}}\stackrel{-2}{{\mathrm{O}}_4}\stackrel{ }{\to }{\mathrm{K}}_2\stackrel{+6}{\mathrm{Mn}}{\mathrm{O}}_4+\stackrel{+4}{\mathrm{Mn}}{\mathrm{O}}_2+\stackrel{\mathrm{O}}{{\mathrm{O}}_2}$

‘Mn’ shows $\downarrow$ in OX. State
‘O’ shows$\uparrow$ in OX. State
It is not a disproprtionation
$\mathrm{B}) 2\mathrm{Na}\stackrel{+5}{\mathrm{N}}{\stackrel{-2}{\mathrm{O}}}_3\stackrel{ }{\to }2\stackrel{+3}{{\mathrm{NaNO}}_2}+\stackrel{\mathrm{O}}{{\mathrm{O}}_2}$

‘N’ Shows $\downarrow$ in Ox. State
‘O’ Shows $\uparrow$in Ox. State

it is also not a disproportionation reaction.