The following summarizes the aging of accounts receivable for Johnston Supplies, Inc. as of July 31, 2019: Number of Days Unpaid Not yet due 1-30 days past due 31-60 days past due Over 60 days past due Total Accounts Receivable $126,600 89,300 53,700 31,900 Historical % Uncollectible 3% 13% 19% 36% Required: a. The unadjusted balance of the Allowance for Doubtful Accounts of Johnston Supplies, Inc. is a credit balance in the amount of $28,977 on July 31, 2019. Prepare the required adjusting entry to record Bad Debt Expense for the year. b. Johnston Supplies, Inc. writes off $3,091 of uncollectible accounts on August 15, 2019. Prepare the required adjusting entry to record the write-off. c. Use a T-account to determine the account balance in the Allowance for Doubtful Accounts on August 15, 2019