Which of the following reactions are disproportionation reaction?
(a) $2Cu^+ \to Cu^{2+} +Cu^0$
(b) $3MnO_4^{2-} + 4H^+ \to 2MnO_4^- + MnO_2 +2H_2O$
(c) $2KMnO_4 \xrightarrow{\Delta} K_2MnO_4+ MnO_2+O_2$
(d) $2MnO_4^-+ 3Mn^ {2+} +2H_2O \to 5MnO_2+ 4H^\oplus$
Select the correct option from the following
(1) (a) and (b) only
(2) (a), (b) and (c)
(3) (a), (c) and (d)
(4) (a) and (d) only
(a) $2Cu^+ \to Cu^{2+} +Cu^0$
(b) $3MnO_4^{2-} + 4H^+ \to 2MnO_4^- + MnO_2 +2H_2O$
(c) $2KMnO_4 \xrightarrow{\Delta} K_2MnO_4+ MnO_2+O_2$
(d) $2MnO_4^-+ 3Mn^ {2+} +2H_2O \to 5MnO_2+ 4H^\oplus$
Select the correct option from the following
(1) (a) and (b) only
(2) (a), (b) and (c)
(3) (a), (c) and (d)
(4) (a) and (d) only