The correct answer is B. Coral reefs can be damaged by careless boat drivers and divers.
Step-by-step explanation:
The text presented includes information related to coral reefs such as the zone where they developed in the ocean, their composition, their role in ecosystems and also the way corals need to be protected as they are delicate. About this last point, the author explains there are different ways corals can be harmed, this includes due to boaters drivers, divers, hotel building and also water contamination. According to this, a concrete example of how coral reefs are fragile and can be damaged is that coral reefs can be damaged by careless boat drivers and drivers.