The Efficient Price to Charge Consumers for Their Use of a Public

The efficient price to charge consumers for their use of a public good is

A) equal to the price that the free market would achieve.
B) equal to the average per- person cost of providing this good.
C) that price that prevents free riding by some consumers.
D) equal to the cost of providing the good to one additional consumer.
E) equal to the highest individual marginal benefit from consuming a unit of the good.