TOEFL Listening: TPO-TOEFL阅读TPO - TH57P_856BZGK744N$

Why does the author mention a "picnic area" in paragraph 1? A. to identify a site where a variety of different species of chipmunks can be seen B. to support the point that each species of chipmunk inhabits a distinct location C. to emphasize the idea that all species of chipmunks have a similar appearance D. to provide an example of a location to which chipmunks are likely to scurry for food