The passage is structured to lead to which of the following as a conclusion? A. The use of biodiesel will increase by less than one percent over the next 15 years. B. During the next 15 years, the production of biodiesel will be increased as fast as it is possible to increase it. C. During the next 15 years, it will be impossible, just by switching to biodiesel, to meet the government's stated goal with respect to reducing air pollution. D. Fifteen years from now, the air pollution caused by the production and use of one gallon of regular diesel fuel will be far less than it currently is. E. There will be no significant year-to-year increase in the amount of regular diesel fuel used during the next 15 years.