Final answer:
The correct order of increasing trophic level for the given organisms is Option A: Grass, Rabbit, Fox.
Step-by-step explanation:
The correct order of increasing trophic level for the given organisms is Option A: Grass, Rabbit, Fox.
Trophic levels represent the feeding positions in a food chain or food web. Producers, such as grass, occupy the first trophic level, followed by primary consumers like rabbits at the second trophic level, and then secondary consumers like foxes at the third trophic level.
Therefore, the correct order is A. Grass, Rabbit, Fox.