GMAT Critical Reasoning (CR) | Re: Two years ago, officials in Bedenia implemented landmark

It is stated in the argument that "Gordenia" is a major producer of "marijuana" but that does not indicate other drugs are not produced.Besides the drug legislation has been implemented to combat illegal drug use which includes all drugs. Hence "A" does not explain why the problem has not been curbed. Even if the drug problems in "Bedenia" includes other drugs the use should have reduced after the implementation of the legislation.