While charging the lead storage battery.......

The correct answer is Option (1) → $PbSO_4$ on anode is reduced to $Pb$

During charging of a lead storage battery:

• Anode (where oxidation occurs during discharge) becomes the cathode during charging.
• Cathode (where reduction occurs during discharge) becomes the anode during charging.

Reactions during charging:

1. At the anode (negative plate): PbSO₄(s) + 2e⁻ → Pb(s) + SO₄²⁻ → PbSO₄ is reduced to Pb
2. At the cathode (positive plate): PbSO₄(s) + 2H₂O → PbO₂(s) + SO₄²⁻ + 4H⁺ + 2e⁻ → PbSO₄ is oxidized to PbO₂