To Ensure That All Credit Sales Transactions of an Entity

To ensure that all credit sales transactions of an entity are recorded, which of the following controls would be most effective?

A) On a monthly basis, the accounting department supervisor reconciles the accounts receivable subsidiary ledger to the accounts receivable control account.
B) The supervisor of the accounting department investigates any account balance differences reported by customers.
C) The supervisor of the billing department sends copies of approved sales orders to the credit department for comparison of authorized credit limits and current customer balances.
D) The supervisor of the billing department matches prenumbered shipping documents with entries recorded in the sale journal.