On dissolution of the firm, partners' capital account are closed through :

Bank A/c

The correct answer is Option (3) - Bank A/c

* If the partner’s capital account shows a debit balance after all adjustments, he brings in the necessary cash for which the entry will be:
Bank A/c Dr.
   To Partner’s Capital A/c

* The balance is paid to partners whose capital accounts show a credit balance and the following entry is recorded.
Partners’ Capitals A/cs (individually) Dr.
         To Bank A/c

Thus, partner's capital account are closed through the bank account. It may be noted that the aggregate amount finally payable to the partners must equal to the amount available in bank and cash accounts. Thus, all accounts of a firm are closed in case of dissolution.