Which of the following is not an example of Disproportionation in acidic medium?

Question

$(1) 2Mn^{3+} + 2H_2O \rightarrow Mn^{2+} + MnO_2 + 4H^{+}$ $(2) 3MnO_4^{2-} + 2H_2O \rightarrow MnO_2 + 2MnO_4^{-} + 4OH^{-}$ $(3) 3MnO_4^{2-} + 4H^{+} \rightarrow 2MnO_4^{-} + MnO_2 + 2H_2O$ $(4) 2MnO_4^{-} + 3Mn^{2+} + 2H_2O \rightarrow 5MnO_2 + 4M^{-}$