When an aqueous solution of $CuCl_2$ is electrolysed using $Pt$ inert electrodes,the reactions at the cathode and anode respectively are:

• A
  $4 H_2O_{(l)} + 4 e^{-} \longrightarrow 2 H_{2(g)} + 4 OH^{-}_{(aq)}$; $2 H_2O_{(l)} \longrightarrow O_{2(g)} + 4 H^{+}_{(aq)} + 4 e^{-}$
• B
  $2 Cu^{2+}_{(aq)} + 4 e^{-} \longrightarrow 2 Cu_{(s)}$; $2 H_2O_{(l)} \longrightarrow O_{2(g)} + 4 H^{+}_{(aq)} + 4 e^{-}$
• C
  $Cu^{2+}_{(aq)} + 2 e^{-} \longrightarrow Cu_{(s)}$; $2 Cl^{-}_{(aq)} \longrightarrow Cl_{2(g)} + 2 e^{-}$
• D
  $2 H_2O_{(l)} + 2 e^{-} \longrightarrow H_{2(g)} + 2 OH^{-}_{(aq)}$; $2 Cl^{-}_{(aq)} \longrightarrow Cl_{2(g)} + 2 e^{-}$