The main purpose of this passage is___________

Câu hỏi: Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 35.
Sylvia Earle, a marine botanist and one of the foremost deep-sea explorers, has spent over 6,000 hours, more than seven months, underwater. From her earliest years, Earle had an affinity for marine life, and she took her first plunge into the open sea as a teen ager. In the years since then she has taken part in a number of landmark underwater projects, from exploratory expeditions around the world to her celebrated "Jim dive" in 1978, which was the deepest solo dive ever made without cable connecting the diver to a support vessel at the surface of the sea.
Clothed in a Jim suit, a futuristic suit of plastic and metal armor, which was secured to a manned submarine, Sylvia Earle plunged vertically into the Pacific Ocean, at times at the speed of 100 feet per minute. On reaching the ocean floor, she was released from the submarine and from that point her only connection to the sub was an 18 foot tether. For the next 2 1/2 hours, Earle roamed the seabed taking notes, collecting 15 specimens, and planting a U.S. flag. Consumed by a desire to descend deeper still, in 1981 she became involved in the design and manufacture of 20 deep-sea submers ibles, one of which took her to a depth of 3,000 feet. This did not end Sylvia Earle's accomplishments.
The main purpose of this passage is___________
A. to explore the botany of ocean floor
B. to present a short biography of Sylvia Earle 1980
C. to provide an introduction to oceanography
D. to show the historical importance of the Jim dive