Which of the Following Would Represent Proper Segregation of Duties

Which of the following would represent proper segregation of duties?

A) The employee who has custody of cash also does accounts receivable record keeping.
B) The employee who has custody of cash completes the bank reconciliation.
C) The employee who opens mail containing checks prepares a list of checks received.
D) The employee who opens mail containing checks records transactions in the general ledger.