Answer: The correct answer is-
C. Plants.
Primary producers are those organisms that can synthesize their own food using carbon dioxide and water in the presence of sunlight ( photosynthesis).
They occupy the first trophic level in a food chain ( where transfer of energy takes place between different organisms) within an ecosystem. Therefore, they for the base of any food chain.
Example- Green Plants and algae.
Thus, option C) Plants is the right answer.
