Which One of the Following Functions Performed in an Organization

Which one of the following functions performed in an organization is a violation of internal control?

A) A mail clerk opening the mail compares the cheque received with the source document accompanying the payment, noting the amount paid, then forwards the cheques daily along with a listing of the cash receipts) to the Cashier for deposit
B) A mail clerk opening the mail compares the cheque received with the source document accompanying the payment, noting the amount paid, then forwards the source documents that accompany the payments along with a listing of the cash receipts) to Accounts Receivable, on a daily basis, for posting to the subsidiary ledger
C) At the end of the week the Cashier prepares a deposit slip for all of the cash receipts received during the week
D) The General Ledger clerk compares the summary journal entry, received from the Cashier for cash receipts applicable to outstanding accounts, with the batch total for posting to the Subsidiary Ledger by the Accounts Receivable clerk