Each step or level of a food chain forms a trophic level. Which of the following is at the first trophic level of the said food chain?

In an ecological food chain, the first trophic level is occupied by autotrophs or primary producers (like green plants) that produce their own food using solar energy. Herbivores occupy the second trophic level, carnivores occupy the third level, and top carnivores form the higher levels.