TOEFL Listening: ETS-TOEFL听力机经 - 03FVWAMYR3EO9C35P$

What does the professor imply about the industrial-scale production of ethanol in the United State? A. It is the best option for future energy production in the United States. B. It is a model for ethanol production in other countries. C. Its efficiency is likely to improve in the near future. D. It is energy intensive and inefficient.