I think the correct answer would be C. The best summary of the text "Save the Coral Reefs" would be
Construction along the coasts, overfishing, and bleaching have seriously damaged the world’s coral reefs. Since reefs are a very important part of the ocean’s ecosystem, their destruction has a devastating environmental impact, and we must work to protect them. Coral reefs are known to be very fragile which are made of limestone. People who would build coastal regions and those who overfish should be stopped as these activities ruin and damage the corals which would ruin the habitat of the fishes and other aquatic organisms.
