Final answer:
The most widely used illegal drug in the United States is marijuana. Hence the correct answer is option A
Step-by-step explanation:
The most widely used illegal drug in the United States is marijuana. According to the FBI, each year police arrest around 1.5 million people for various drug abuse violations, and marijuana-related offenses are easily the most numerous of those crimes. Additionally, the Pew Research Center found that a majority of people in the United States favored legalizing marijuana in 2013.
Hence the correct answer is option A