Direct current is passed through a copper sulphate solution

Direct current is passed through a copper sulphate solution using platinum electrodes. The elements liberated at the electrodes are

1. copper at anode and sulphur at cathode
2. sulphur at anode and copper at cathode
3. oxygen at anode and copper at cathode
4. copper at anode and oxygen at cathode

In the electrolysis of CuSO4, oxygen is liberated at anode and copper is deposited at cathode.