Swordfish Inc$$s account balances at December $31,2021$ for Accounts Receivable and the related Allowance for Doubtful Accounts are $$920,000$ debit and $$2,100$ credit, respectively. From an aging of accounts receivable, it is estimated that $$39,000$ of the December $31$ receivables will be uncollectible. The necessary adjusting entry would include a credit to the allowance account for

a$.$ $$39,000$

b$.$ $$41,100$

c$.$ $$36,900$

d$.$ $$2,100$