What distinguishes over-the-counter (OTC) drugs from prescription drugs?

Over-the-counter (OTC) drugs are primarily characterized by their availability for purchase without the need for a prescription from a healthcare provider. This accessibility is based on the established safety profile and low potential for misuse of these medications when used as directed. Consumers can self-diagnose minor health issues and obtain these medications directly from pharmacies, supermarkets, and other retail outlets, reflecting the trust in the consumer's ability to safely use these products.

In contrast, prescription drugs typically require the oversight of a healthcare professional due to their complexity, potential side effects, higher risk of misuse, or necessity for monitoring during treatment. The regulatory framework recognizes that while OTC medications are suitable for self-management of certain conditions, prescription medications often need a provider's expertise to ensure safe and effective use.

The other options contain inaccuracies or misinterpretations of the parameters that define OTC and prescription drugs, focusing on aspects that do not effectively capture the essence of the distinction. Thus, the criterion that OTC drugs can be purchased without a prescription is the clear differentiator.