单选题 Why do some birds vary from place to place in their song repertoires of according to DK?

A、 It comes about perhaps because of the change of their DNA.
B、 It comes about simply due to imitation of the other birds' manner.
C、 Because the birds have learned the local dialect by learning the local dialect from generation to generation.
D、 Both A and

【正确答案】 D

【答案解析】文中第七段给出了不同地区鸟类技能不同的两个原因，一是the song being encoded right in their DNA，另一个原因是the birds have learned the local dialect。