Answer:
The correct answer is D: "host symbionts with colorful photosynthetic pigments"
Step-by-step explanation:
Healthy corals are brightly colored because they host symbionts with colorful photosynthetic pigments
Corals are translucid or white. They can host different organisms that live on and among them, giving place to an amazing ecosystem.
One of these organisms is the photosynthetic unicellular microalgae, called zooxanteles, that are colorful and provide nutrients to the coral.
When changes in radiation, temperature or salinity in water occur, corals react to these changes losing these algae and becoming translucid again.