Which ion undergoes disproportionation in an aqueous solution?

Which of the following reactions are disproportionation reactions?
$(a)$ $2 Cu^{+} \rightarrow Cu^{2+} + Cu^{0}$
$(b)$ $3 MnO_{4}^{2-} + 4 H^{+} \rightarrow 2 MnO_{4}^{-} + MnO_{2} + 2 H_{2}O$
$(c)$ $2 KMnO_{4} \xrightarrow{\Delta} K_{2}MnO_{4} + MnO_{2} + O_{2}$
$(d)$ $2 MnO_{4}^{-} + 3 Mn^{2+} + 2 H_{2}O \rightarrow 5 MnO_{2} + 4 H^{+}$
Select the correct option from the following:

Which of the following compounds undergoes disproportionation in the presence of $SO_3$ gas?

Assign $A, B, C, D$ from the given type of reaction.
$I_2 + 2NaOH \longrightarrow NaI + NaOI + H_2O$

In the reaction $P_4 + 3KOH + 3H_2O \to PH_3 + 3KH_2PO_2$,phosphorus is .........

An example of a disproportionation reaction is