The last step in the revenue cycle is cash collections. The accounts receivable department must know when customers pay their invoices, yet segregation of duty controls dictate that the collection and recording functions be kept separate from each other. What is a solution to this potential internal control problem?

a. have mailroom personnel prepare a remittance list which can be forwarded to accounts receivable

b. have customers send a remittance advice with their payment

c. establish a lockbox arrangement with a bank

d. all of the above