Which of the following best describe the function of the highlighted sentence? A. It identifies a factor that complicates biologists' ability to draw conclusions about the behavior of cetaceans in their natural environments. B. It illustrates the kind of deduction mentioned in the preceding sentence. C. It explains why skeptics have remained unpersuaded by evidence that has been put forward in support of the claim that cetaceans have culture. D. It introduces a claim that would be dismissed by both supporters and opponents of the view that cetaceans have culture. E. It notes a previously overlooked factor that might shed light on the question of whether cetaceans have culture.