Addy Weddings uses the balance sheet approach to estimate uncollectible receivables. The aging of receivables on December 31,2021 is shown in part a). Required a) Calculate the required allowance for doubtful accounts. Do not enter dollar signs or commas in the input boxes. Round all answers to the nearest whole number. b) Prepare the journal entry on December 31, 2021 to record bad debt expense, assuming the allowance account has a $3,400 credit balance. c) Prepare the journal entry on December 31, 2021 to record bad debt expense, assuming instead that the allowance account has a $22,000 credit balance. d) Prepare the journal entry on December 31, 2021 to record bad debt expense, now assuming the allowance account has a $1,800 debit balance