The correct option is C III
Autotrophs like grass that obtain the energy from the sun and convert it to chemical energy. Hence, it is a producer. Energy from the grass is obtained by herbivores. Hence, they are present at the second trophic level called primary consumers.
The energy from primary consumers is obtained by the secondary consumers which are present at the third trophic level, also known as secondary consumers or primary carnivores. The fourth trophic level is occupied by tertiary consumers. Hence, option c is correct.