What information is NOT required on a prescription label?

The answer correctly identifies that the expiration date of the medication is not a required element on a prescription label. While ensuring that patients are aware of the medication's expiration date is essential for safety and efficacy, it is primarily a concern for inventory and storage rather than a legal requirement for labeling prescriptions.

In many jurisdictions, prescription labels typically need to include key information like the name of the patient, the prescription number, and the name and address of the pharmacy. These components are crucial for identifying the medication, ensuring correct dispensing, and providing a means of contacting the pharmacy for questions or refill requests. The absence of an expiration date on a prescription label does not violate legal requirements, as it's understood that pharmaceutical companies provide this information on the product packaging itself.

Thus, the lack of a requirement for an expiration date on the prescription label is why this choice is indeed the correct answer.