Which of the following reactions are disproportionation reactions ?

(i)    ${\text{2Cu}}^{\text{+}}\to {\text{Cu}}^{\text{2+}}{\text{+Cu}}^{\text{0}}$
(ii)  ${\text{3MnO}}_{\text{4}}^{\text{2-}}{\text{+4H}}^{\text{+}}\to {\text{2MnO}}_{\text{4}}^{\text{-}}{\text{+MnO}}_{\text{2}}{\text{+2H}}_{\text{2}}\text{O}$
(iii)  $2{\mathrm{MnO}}_4\to {\mathrm{K}}_2{\mathrm{MnO}}_4+{\mathrm{MnO}}_2+{\mathrm{O}}_2$
(iv)  ${\text{2MnO}}_{\text{4}}^{\text{-}}{\text{+3Mn}}^{\text{2+}}{\text{+2H}}_{\text{2}}\text{O}\to {\text{5MnO}}_{\text{2}}{\text{+2H}}^{\text{+}}$
Select the correct option from the following.

The redox reaction in which one element of reactions undergo oxidation as well as reduction is called disproportion redox reactions.

${\text{3MnO}}_{\text{4}}^{\text{-2}}{\text{+4H}}^{\text{+}}\stackrel{\Delta }{\to }{\text{2MnO}}_{\text{4}}^{\text{-}}{\text{+MnO}}_{\text{2}}{\text{+2H}}_{\text{2}}\text{O}$

called disproportion redox reaction .

(1)  ${\text{2Cu}}^{\text{+}}\to {\text{Cu}}^{\text{+2}}{\text{+Cu}}^{\text{o}}\text{:}$
 Disproportion redox reaction
(3)   ${\text{2MnO}}_{\text{4}}\stackrel{\Delta }{\to }{\text{K}}_{\text{2}}{\text{MnO}}_{\text{4}}{\text{+MnO}}_{\text{2}}{\text{+O}}_{\text{2}}$
This reaction is not possible because reactant ${\text{(MnO}}_{\text{4}})$ does not exist.
(4)  ${\text{2MnO}}_{\text{4}}^{\text{-}}{\text{+3n}}^{\text{2+}}{\text{+2H}}_{\text{2}}\text{O}\to {\text{5MnO}}_{\text{2}}{\text{+2H}}^{\text{+}}$
Comproportionation redox reactions.