TOEFL Reading: ETS-TOEFL阅读机经 - PH766HX6I3W6T9M6L$

In paragraph 5, why does the author discuss the begging behavior of a hatchling bird? A. To support the view that instinct explains animal behavior better than learning does B. To demonstrate that ethologists are correct about the limited ability of animals to learn C. To contrast an ethologist's explanation of a particular animal behavior with that of a comparative behaviorist D. To question whether the discussion about the roles of nature and nurture was a valid one