In 2021, Warehouse 13 had net credit sales of $757000. On January 1, 2021, Allowance for Doubtful Accounts had a credit balance of $15980. During 2021, $28990 of uncollectible accounts receivable were written off. Past experience indicates that the allowance should be 10% of the balance in receivables (percentage of receivable basis). If the accounts receivable balance at December 31 was $155000, what is the required adjustment to the Allowance for Doubtful Accounts at December 31, 2021? $155000 $28990 $28510 $31480