TOEFL Listening: ETS-TOEFL听力机经 - I7831QW394M3OUOSP$

Why did researchers conclude that the taro remains found near Kuk were a result of farming? A. Taro does not grow wild in highland areas. B. Taro is a native plant of China. C. Taro was only found in a very small area at Kuk. D. Taro normally does not grow in humid climates.