Final answer:
Marijuana remains illegal under the federal Controlled Substances Act, despite some states legalizing it for medicinal and recreational use.
Step-by-step explanation:
In regard to marijuana laws, option b) Marijuana remains illegal under the federal Controlled Substances Act is true. The Controlled Substances Act (CSA), passed by Congress in 1970, classifies marijuana as a Schedule 1 drug, which means it is considered to have a high potential for abuse and has no accepted medical use.
Although some states have legalized marijuana for medicinal and recreational use, federal law still criminalizes its possession, sale, and use. The federal government has the authority to enforce these laws, but it relies on the cooperation of states.
Therefore, while there may be variations in marijuana laws across states, marijuana remains illegal under federal law.