According to convention, an electrochemical reaction can be represented as Reaction at anode || Reaction at cathode. The || represents the salt bridge. The reaction in question shows the anodic reaction of Mg which gets oxidized to Mg²⁺ and the cathodic reaction is Cu²⁺ which gets reduced to Cu and is deposited on the cathode. The combined half-cell reactions can be represented as

Mg → Mg²⁺ + 2e^- at anode and Cu²⁺ + 2e^-→ Cu(s) at cathode. Combined, it forms Mg + Cu²⁺→ Mg²⁺ + Cu.

Hence, the correct options are (ii) and (iii).