The Ogallala aquifer is a large underground pool of fresh water under several western states in the United States. Any farmer with land above the aquifer can at present pump water out of it. We might expect thatA over time, the aquifer is likely to be overused.B each farmer has a sufficient incentive to conserve the water.C state governments have an incentive to insure that their farmers do not overuse the water.D resources would be used more efficiently if the government paid for the pumps farmers use to get the water.