TOEFL Reading: ETS-TOEFL阅读机经 - Q34253_C8L4673_NL$

What can be inferred from paragraph 2 and 3 about the volcanic rock found by the geologists in the Marshall Islands? A. It extends from the surface to 1,283 meters deep. B. It was the first guyot ever discovered by researchers. C. It formed after the limestone layers of the Eriwetok atoll. D. It was once an island existing above the ocean surface.