Final answer:
The comparison of postings of cash receipts to accounts with the details of cash deposits is the best audit procedure for detecting lapping since it can uncover discrepancies indicative of such fraud.
Step-by-step explanation:
The question relates to the best audit procedure for the detection of lapping. Lapping is a sort of fraud involving the delay in recording accounts to cover up theft of cash. Out of the options provided, comparison of postings of cash receipts to accounts with the details of cash deposits is the most effective procedure. This comparison can help in identifying discrepancies where cash intended for one account may have been used to cover a shortage in another, which is a common sign of lapping. While the confirmation of the cash balance, reconciliation of the cash account balances, and preparing a proof of cash are essential auditing procedures, they might not directly reveal lapping because they do not necessarily track the flow of individual transactions as they are recorded in the accounting system.