16. Which statement about energy use in the United States is correct?
a. The United States has the world's highest fuel economy standards,
b. The United States is the world's leading producer of wind energy.
c. The United States lacks sites that can be used for geothermal energy.
d. The United States does not subsidize ethanol duc to corn's high nct energy,
e. The United States uses cogeneration to produce more than half its energy