TOEFL Listening: ETS-TOEFL听力机经 - 691V82T5B3MADI74P$

What does the professor point out about the northern rim of the south pole Aken basin? A. It contains the largest grouping of strong local magnetic fields on B. it is composed of rock formed from erupting volcanoes C. it contains large regions of newly formed rock D. it consist mainly of one type of rock