Answer:
C. Habitat
Step-by-step explanation:
Simply by knowing that D. Biosphere talks about what lives on land or what lives in water( like a whole Jungle or an whole ocean), B. Biome ( I think ) means the whole Earth, and A. Ecosystem is out of the question because the question already tells you what an Ecosystem is...so C. Habitat. Also when thinking of a Habitat, think of how in a zoo, people try to create a small part of the area from their ecosystem.