Use the following to answer questions 20-22 At the beginning of the year; MB, Inc.'s allowance for uncollectible accounts had a beginning balance of $5,000. On January 22nd, MB wrote off the A/R from customer C for $620 20. Record the entry for write-off 21. $ 22. $ By the end of the year (December 31"); total accounts written off were $4,920 (including the write off for customer C). What is the balance in the allowance for uncollectible accounts after all the write- offs? How much did bad debt expense change when the company wrote off the accounts receivables?