If Ethanol Production in the United States More Than Doubles

If ethanol production in the United States more than doubles between 2015 and 2022,it will need to rely on

A) even more corn that will not be available to feed the hungry people of the world.
B) second-generation biofuel using enzymes that convert cellulose to fermentable sugar.
C) manure and other animal wastes to generate methane,which in turn is used to produce alcohol.
D) any plant material and enzymes that convert sugars into cellulose,methane,and oxygen.