Which of the following refers to medications that require a doctor's order due to their controlled substance status?

The correct choice refers to medications that require a doctor's order because they fall under the category of controlled substances. Prescription medications are specifically regulated and require a licensed healthcare provider to evaluate the patient's condition and determine the appropriate treatment before they can be dispensed. This is crucial for medications that have a higher potential for abuse or dependence, ensuring that they are used safely and effectively in the right clinical context.

This regulation is in place to protect patients and ensure that the use of strong or potentially dangerous medications is monitored by a healthcare professional. On the other hand, non-controlled medications do not carry the same restrictions, OTC (over-the-counter) medications can be purchased without a prescription, and self-administered medications might not necessarily need a doctor's order depending on their classification and the patient's condition. Thus, the requirement for a doctor's order is what distinguishes prescription medications in this context.