During the electrolysis of copper sulphate aqueous solution using copper electrodes,the reaction taking place at the cathode is:

• A
  $Cu \longrightarrow Cu^{2+}_{(aq)} + 2e^{-}$
• B
  $Cu^{2+}_{(aq)} + 2e^{-} \longrightarrow Cu_{(s)}$
• C
  $H^{+}_{(aq)} + e^{-} \longrightarrow \frac{1}{2} H_{2(g)}$
• D
  $S{O_{4}}^{2-}_{(aq)} \longrightarrow SO_{3(g)} + \frac{1}{2} O_{2(g)} + 2e^{-}$