At the beginning of the year, the balance in Allowance for Doubtful Accounts is a credit of $669. During the year, $422 of previously written off accounts is reinstated and accounts totaling $771 are written off as uncollectible. The end-of-year balance (before adjustment) in Allowance for Doubtful Accounts should be Oa. $669 Ob. $320 Oc. $771 Od. $422