Sudan Ltd.'s allowance for doubtful accounts was $85,000 at the end of 2017 and $105,000 at the end of 2016. For the year ended December 31, 2017, Sudan reported bad debt expense of $18,000 in its income statement. What amount did Sudan debit to allowance for doubtful accounts during 2017 to write off actual bad debts?
$38,000
$34,650
$20,000
$12,000