In the event of dissolution of a partnership firm, the provision for doubtful debts is transferred to:

Realisation account

The correct answer is option 4- Realisation account.

All asset accounts excluding cash, bank and fictitious assets, if any are closed by transfer to the debit of Realisation Account at their book values. It may be noted that sundry debtors are transferred at gross value and the provision for doubtful debts is transferred to the credit side of the Realisation Account along with liabilities. The same thing will apply to fixed assets, if provision for depreciation account is maintained.