What was the most likely cause of a shift in drug policy during the obama administration?

increasing drug smuggling across the mexican border

decreasing demand for the more addictive drugs

the continual increase in the arrest rate of drug users

new laws that legalized the use of some drugs

"The continual increase in the arrest rate of drug users" is the one reason among the choices given in the question that was the most likely cause of a shift in drug policy during the Obama administration. The correct option among all the options that are given in the question is the third option or the penultimate option.

Marshall plan is the answer.