Which of the following documents should cashiers secure in a locked safe or drawer?

The option regarding cash records is the correct choice because cash records are sensitive financial information that must be protected to maintain integrity and security within financial operations. These records include transaction logs, cash reconciliation reports, and any documentation that details cash handling procedures. By securing cash records in a locked safe or drawer, cashiers help to prevent unauthorized access and potential fraud, ensuring that financial discrepancies can be minimized.

The other options, while important, do not carry the same level of requirement for security. Form 645 pertains to specific reporting but does not hold cash value or sensitive information in the same way cash records do. Items for sale should be displayed for customers and do not need to be secured in the same manner as cash records, and customer receipts are typically not considered sensitive enough to warrant locking away, as they serve as proof of transactions for customers. Thus, while securing various items is essential, cash records necessitate the highest level of security due to their direct relation to the financial transactions of the operation.