Which of the Following Proposals Could Be an Example of an Effort

Which of the following proposals could be an example of an effort to correct for an adverse selection problem?

A) An employer requires all employees to submit to drug testing.
B) The government subsidizes the consumption of fitness activities.
C) An employer that requires all employees to purchase the employer- sponsored dental insurance program.
D) The government imposes a tax on factory- emissions of a toxic substance.
E) The government subsidizes the development of eco- friendly production methods.