Final answer:
The nematodes are located only in the 3rd trophic level of the soil food web.
Step-by-step explanation:
The 3rd trophic level in a soil food web typically consists of organisms that feed on detritus, or decaying organic matter. Among the given options, the organism that is exclusively located at the 3rd trophic level in the soil food web is nematodes. Nematodes are microscopic worms that feed on bacteria, fungi, and other organic material present in the soil.
Learn more about Energy Transfer