Which Statement Describes the Role of Photosynthesis in an Ecosystem

Which statement describes the role of photosynthesis in an ecosystem?

A) Primary producers convert chemical energy to light energy.
B) Primary consumers rely directly on light energy.
C) Primary producers convert light energy to chemical energy as a service to the ecosystem, not for their own gain.
D) Primary consumers rely on primary producers to make light energy available in a usable form.
E) Primary producers make no contribution to the flow of energy into the ecosystem.