Paper 1 February/March 2017 Accounting (9706/12) A Level

Ali’s trade receivables at 31 December 2019 were $\$ 26500$. He knew that $\$ 400$ of these were irrecoverable.
He wished to maintain a provision for doubtful debts equal to 5% of the trade receivables.
At 1 January 2019 the balance of the provision for doubtful debts was $1200.
Which entry does Ali make in the provision for doubtful debts account at 31 December 2019?