单选题：根据下面内容，回答题：There has been, in history, a man who was swallo

根据下面内容，回答题：
There has been, in history, a man who was swallowed by a whale and lived to tell the tale. Theman's name is James Bartley. The records to prove his unusual experience are in the British Admiralty.Bartley was making his first trip on the whaling ship Star of the East. Suddenly the lookoutsighted a huge sperm whale. The whalers knew it was a huge whale by the size of the spray it blewinto the air. They lowered their small boats. James.Bartley was in the first longboat. The men roweduntil they were close to the whale. A harpoon was thrown and it found its mark. It sank into thewhale's flesh. The maddened beast crashed into the boat, snapping its tail at the men and the wreck-age of their boats. When the survivors were picked up, James Bartley was missing.
Shortly before sunset, the whale was finally captured. The sailors tied the whale's dead body tothe side of the ship. Because of the hot weather it was important that they cut up the whale rightaway. Otherwise, the meat would 'begin to rot and the oil would begin to spoil. When they got to thestomach,they felt something moving about wildly. They thought it would be a big fish still alive in-side. But when they opened the stomach they found James Bartley. After this trip, Bartley settled inEngland, and never returned to sea.
This passage is mainly about __________ . A．how to hunt whales for their oil and meat
B．the hard and dangerous lives that whalers had to live
C．the duties of each man on a whaling ship
D．a man who was swallowed by a whale and lived