Answer:
The correct answer is a. carnivores.
Photosynthesis is the process by which plants make their food from carbon dioxide and water in the presence of sunlight and chlorophyll. Hence, they convert light energy into chemical energy (food or glucose).
This energy is first utilized in the cellular respiration and then the rest in transferred to the primary consumers i.e. herbivores which feed on green plants.
They use this energy in their metabolic processes. The rest is transferred to the secondary consumers i.e. carnivores which feed on the herbivores.
Hence, energy from the photosynthesis indirectly passes to the carnivores via herbivores.