What happens due to coral reef damage by El Niño?

The correct answer to the question is B, the fish that depend on the reef die. Fish depend on the reef for food, shelter and a breeding ground, so when the reef is destroyed, the fish no longer have a place to hide from predators. It also means that the life dependent on the reef now have to venture out to find other food and shelter, which leaves them out in the open for predators.