Receipts for employee expenses are a detective control because they help to uncover any fraudulent claims by requiring documentation and review of expenses incurred. This allows for the verification of authenticity and accuracy, thus managing the risk of fraud. Awareness of prior incidents of fraud is more of a preventive control, contractor non-disclosure agreements are preventive, and verification of currency exchange rates is primarily a corrective or investigative measure, but not focused specifically on detecting fraud in the context of expenses.