Which of the following substances are specifically mentioned as not tolerated in the USAF?

The correct answer highlights the specific substances that the United States Air Force (USAF) explicitly identifies as intolerable due to the potential negative impact they can have on military readiness and effectiveness. Illegal drugs are particularly noted for their prohibition given the broader implications they have on safety, discipline, and operational integrity. Additionally, alcohol is also addressed because, while it is legal, excessive consumption can lead to behavioral issues, health problems, and impairment, which contradicts the USAF's standards for personnel conduct.

While alcohol is mentioned, other options do not fully encompass the extensive guidelines and regulations that the USAF follows concerning substance use. For example, while tobacco use might be discouraged due to health reasons, it is not as stringently prohibited as illegal drugs and alcohol. Prescription medications could also be tolerated under specific regulations if they are used correctly and do not impair a service member's ability to perform duties. Lastly, caffeine products, although they may have recommendations on consumption for health, are generally permitted and are not mentioned as intolerable.

By focusing on the impact of illegal drugs and alcohol, the USAF aims to maintain a disciplined, functional, and healthy force—hence their specific stance on these substances.