In paragraph 4, why does the author discuss the reefs around the Indonesian Islands, the Philippines, New Guinea, Fiji, and the Caribbean Islands? A. To argue that these islands have suitable environmental conditions for subsidence B. To support the claim that the subsidence theory cannot explain the formation of all barrier and fringing reefs. C. To indicate how different barrier and fringing reefs could be from atolls D. To identify reefs that grow around non-volcanic islands