The correct choice is (b) Algae and the corals
Easy explanation: Resource-resource mutualism -A relationship where one resource is traded for another. Corals and the symbiotic algae .The algae get inorganic nutrients from the corals, and the corals get sugars that are by-products of photosynthesis from the algae. When a coral ‘bleaches’ it is actually kicking out the zooxanthellae that live in it, so all you see is the coral’s skeleton, which is white.