United Company Uses the Allowance Method of Recording Credit Losses

United Company uses the allowance method of recording credit losses. In November 2019, United wrote off the $1,800 account of Gamma Company. In January 2020, Gamma paid the $1,800.
The entry or entries to record the payment is/are:

A) Cash 1,800
Recoveries of Accounts Written Off 1,800
B) Accounts Receivable-Gamma Co. 1,800
Allowance for Doubtful Accounts 1,800
Cash 1,800
Accounts Receivable-Gamma Co. 1,800
C) Allowance for Doubtful Accounts 1,800
Accounts Receivable-Gamma Co. 1,800
D) Accounts Receivable-Gamma Co. 1,800
Bad Debts Expense 1,800
Cash 1,800
Accounts Receivable-Gamma Co. 1,800