Ans. (C). kelp.
In an ecosystem, the most of the energy is available for organisms present in trophic level. These organisms include all photosynthetic, autotrophs (producers) that make food by using solar energy. As energy gets transferred from a lower to higher trophic level, only 10 percent of total energy gets transferred, so consumers get less energy than producers.
In given ecosystem, kelp is producer that makes food for ecosystem. Thus, the correct answer is option (c).
