TOEFL Listening: TPO-TOEFL阅读TPO - O7250440JL14AUBUN$

The author remarks that "Lightning that strikes the ground is the most likely to be destructive" in order to explain why A. this form of lightning has been investigated so much B. this form of lightning is not as common as lightning within a cloud C. scientific understanding of this form of lightning is important D. the buildup of positive charge on the ground beneath a storm cloud can have serious consequences