Where are fungus gnats typically found?

Fungus gnats are primarily found in potted plants, as they thrive in the moist, organic conditions typically present in the soil of these plants. These small, dark flies are particularly attracted to the moist soil where they lay their eggs, as the decaying organic matter provides an ideal environment for their larvae to feed and develop.

While these gnats can be present in soil (which is related to potted plants), their association is more specifically tied to the pots themselves, where conditions are optimal for their life cycle. Other environments such as water sources and animal burrows do not provide the necessary conditions for fungus gnats to thrive. Therefore, the presence of fungus gnats in potted plants highlights their ecological role and the importance of soil moisture for their reproduction and growth. This characteristic makes option B the most accurate choice.