In a Deciduous Oak Forest in the Northeastern United States

In a deciduous oak forest in the northeastern United States, one example of a nonliving component of the ecosystem is

A) the smaller plants living under the oak trees.
B) nematodes in the soil that feed on dead organic matter.
C) animals such as deer that migrate through the forest but do not eat in the forest.
D) nematodes in the soil that feed on plant roots.
E) sunlight that filters through the canopy.