Which of the following is NOT required on a prescription?

The correct choice is the expiration date, as it is not a requirement on a prescription. When a prescriber writes a prescription, the essential components typically include the patient's name, directions for use, and the pharmacy's address. These elements ensure that the medication is accurately dispensed and that the patient understands how to take their medication.

In contrast, an expiration date is relevant to the drug itself, indicating how long the medication remains effective and safe to use, but it does not need to be included on the prescription itself. The expiration date will be found on the medication packaging or labeling, which is managed by the pharmacy upon dispensing. This distinction helps clarify the primary purpose of a prescription as an order for medication administration rather than a record of the product's stability or safety over time.