TOEFL Listening: ETS-TOEFL听力机经 - YS4D7M6IYS94E51KP$

Why does the professor discuss the minimum-till farming method? A. To question that this method is most useful in small gardens B. To question whether this method is environmentally responsible C. To indicate an efficient method for removing superweeds from fields D. To support her point about the importance of controlling superweeds