In which of the following transformations, oxygen is not the reducing agent?

In the reaction

 $\mathrm{Cu}+{\mathrm{H}}_2{\mathrm{SO}}_4⟶{\mathrm{CuSO}}_4+{\mathrm{H}}_2\mathrm{O}+{\mathrm{SO}}_2$

Select the correct statements from the following:

Find the value of $\mathrm{n}$ in the reaction: ${\mathrm{MnO}}_4^{-}+8{\mathrm{H}}^{+}+{\mathrm{ne}}^{-}⟶{\mathrm{Mn}}^{2+}+4{\mathrm{H}}_2\mathrm{O}$

Balance the following equations :

${\mathrm{BaCrO}}_4+\mathrm{KI}+\mathrm{HCl}⟶{\mathrm{BaCl}}_2+{\mathrm{I}}_2+\mathrm{KCl}+{\mathrm{CrCl}}_3+{\mathrm{H}}_2\mathrm{O}$