$5.$ At December $31,2020,$ Carlson Enterprises had accounts receivable of $ $750,000.$ On January $1,2020,$ Allowance for Doubtful Accounts had a credit balance of $ $18,000.$ During $2020,$ $ $30,000$ of uncollectible accounts receivable were written off. Past experience indicates that $3\%$ of accounts receivable become uncollectible. What should be the bad debt expense for $2020?$A$)$ $ $30,000$B$)$ $ $22,500$C$)$ $ $34,500$D$)$ $ $10,500$