An Efficient Amount of a Public Good Is Unlikely to Be

An efficient amount of a public good is unlikely to be produced in a free market because

A) of the existence of moral hazard.
B) there is no way to prevent a person who is not willing to pay for the good from receiving benefits from the good.
C) social benefits exceed social costs.
D) of the high cost of producing the public good.
E) of the existence of adverse selection.