MnO2+KOH+O2→K2MnO4+H2O (A) $\begin{aligned}
& \mathrm{K}_2 \mathrm{MnO}_4 \xrightarrow{\text { Neutral/acidic solution }} \mathrm{KMnO}_4+\mathrm{MnO}_2 \
& \mathrm{Mn}^{+4}:-[\mathrm{Ar}] 3 \mathrm{~d}^3 \
& \mathrm{n}=3, \mu=\sqrt{3(3+2)}=3.87 \text { B.M. }
\end{aligned}$
Nearest integer is (4)