Is It Reasonable to Consider a Human Body to Be

Is it reasonable to consider a human body to be an ecosystem?

A) No. It's just one body. An ecosystem includes a whole system of interacting species.
B) Yes. We have organ systems so that combined with us being an organism makes us an ecosystem.
C) No. An ecosystem is something outside in nature.
D) Yes. Many organisms living in and on "our" environment compete, reproduce, and evolve, so combined, we are a working ecosystem.
E) No. An ecosystem includes abiotic factors. A human is biotic.