Which of the reactions occurs at anode when the electrolysis of ${\mathrm{CuSO}}_{4 }$solution is carried out using copper electrodes? 

The reactions occurs at anode when the electrolysis of ${\mathrm{CuSO}}_{4 }$solution is carried out using copper electrode is $\mathrm{Cu}\to {\mathrm{Cu}}^{2+}+2{\mathrm{e}}^{-}$.

Cu is oxidized at the anode because it has a greater oxidation potential than ${\mathrm{OH}}^{-}$.

$\mathrm{Cu}\to {\mathrm{Cu}}^{2+}+2{\mathrm{e}}^{-}$.

Hence, correct option is A.