Read the passage:

Oil spills from off-shore drilling and shipping are an immense threat to sea otters. Sea otters are dependent on their thick fur to keep them warm. Its unique structure traps air that insulates their bodies from the cold water. When an otter's fur is covered in oil, it can no longer keep the otter warm. This can cause hypothermia and even death. If the otter tries to clean its fur, it will ingest the oil, which is poisonous. In 1989, the Exxon Valdez hit a reef in Alaska. The ship spilled over ten million gallons of oil into the ocean. The U.S. Fish and Wildlife Service believes that anywhere from 4,000 to 10,000 otters died due to this oil spill.

What point does the author make in the passage?

A Oil is poisonous to all wildlife that lives in the water.
B Oil spills are increasing the number of sea otter deaths.
C Over the last 20 years, the number of oil spills has increased.
D Sea otters have dense, thick fur to protect them from oil.