The relationship between them is chlorophyll because that is the only pigment that interacts with the light proteins by transferring excited electrons to the primary electron acceptor.
The answer would be D. The definition of a homologous structure is an organ or body part that appears in different animals and is similar in structure and location, but doesn't necessarily share the same purpose. The birds and rabbits have similar bones in their forelimbs, but one uses them to run and other uses them to fly.