A nurse is reviewing medication prescriptions for a client. For which of the following entries on the client's medication administration record should the nurse request clarification?

A. Levothyroxine 100 mcg PO every morning: This is a standard and appropriate dosing schedule for levothyroxine, typically taken once daily in the morning on an empty stomach for optimal absorption. B. Simvastatin 40 mg PO at bedtime: Simvastatin is best taken in the evening because cholesterol synthesis is highest at night. This dosage and timing are consistent with standard practice and do not require clarification. C. Morphine 4 mg IV every 4 hr PRN for pain: This is an appropriately written as-needed (PRN) order for pain relief. It includes the medication, dosage, route, frequency, and indication, meeting safe prescribing criteria. D. Acetaminophen 500 mg every 4 hr PRN for fever: This prescription lacks a maximum daily dose, which is critical due to the risk of hepatotoxicity with acetaminophen. The nurse should clarify to ensure total daily dosing does not exceed 4,000 mg.