15. There was less food for birds and also for the Prairie dog, _____ lives in holes in the ground.　

　 A. a kind of animal　　　　　　　　 　　　　 B. an animal that　 　　　　　　　　　　　　　　　　　　　　　　　　

　 C. which of a kind of animal　　　　　 　　　　　　 D. a kind of animal of which