$2CuI\to Cu+Cu{I}_2$, the reaction is

The oxidation state of copper in CuI is $+1$, whereas the oxidation state of copper in elemental $Cu$ and $Cu{I}_2$ are $0$ and $+2$ respectively. This data shows that copper undergoes reduction ($+1$ to $0$) as well as oxidation ($+1$ to $+2$).

Therefore option (A) is correct.