Prior to Year-End Adjusting Entries,what Would Explain the Allowance for Uncollectible

Prior to year-end adjusting entries,what would explain the Allowance for Uncollectible Accounts having a debit balance?

A) The amount of cash collections from customers in the current year was less the amount of cash collections from customers in the prior year.
B) The amount of actual uncollectible accounts in the current year was less than the estimate of uncollectible accounts made at the end of the prior year.
C) The amount of credit sales in the current year was greater than the amount of credit sales made in the prior year.
D) The amount of actual uncollectible accounts in the current year was greater than the estimate of uncollectible accounts made at the end of the prior year.