Final answer:
The most widely abused recreational substance among U.S. high school students is alcohol, which is a legal depressant for adults but often misused by younger individuals.
Step-by-step explanation:
The question concerns the identification of the most widely abused recreational substance among U.S. high school students. According to the information provided and general knowledge, the correct answer is A. Alcohol.
Alcohol falls under the category of depressants, which are a class of psychoactive drugs known to slow down brain function. It is legal for adults over the age of 21 in the United States, but widespread underage drinking makes it highly accessible and commonly misused by high school students. It is important to note that while other substances such as cannabis (marijuana), cocaine, and LSD (Lysergic acid diethylamide) are also abused, historical data and patterns of criminal activity often show a higher prevalence of alcohol misuse among adolescents.