Which of the given reactions is not an example of...

Disproportionation reaction, is a type of redox reaction involving simultaneous reduction and oxidation of atoms of the same element from one oxidation state (OS) to two different oxidation states.

$2\mathop{{H}_{2}{O}_{2}}_{- 1} ⟶ 2\mathop{{H}_{2}O}_{- 2} + \mathop{O₂}_{0}$ : Disproportionation

$2{NO}_{2} + {H}_{2}O \to {HNO}_{3} + {HNO}_{2}$ : Disproportionation

${MnO}_{4}^{-} + 4{H}^{+} + 3{e}^{-} \to {MnO}_{2} + 2{H}_{2}O$ : reduction only

$3{MnO}_{4}^{2 -} + 4{H}^{+} \to 2{MnO}_{4}^{-} + {MnO}_{2}^{+ 4} + 2{H}_{2}O$ : Disproportionation