Which of the following is NOT classified as a controlled substance?

The classification of controlled substances is based on the potential for abuse, dependence, and the necessity of regulation to ensure safe use. Narcotics, benzodiazepines, and controlled drugs fall under this classification due to their potential for abuse and the associated regulations involving their prescription and distribution.

Alcohol, while it can be regulated, is not categorized as a controlled substance in the same manner. It is legal for adult consumption and is regulated through different laws rather than the controlled substances act. Therefore, alcohol does not fit into the same framework as the other choices, which are specifically listed and strictly regulated as controlled substances due to their potential for misuse and abuse. This distinctive regulation makes it clear why alcohol is not classified alongside narcotics, benzodiazepines, or other controlled drugs.