(2) scientists + v.(忘了什么动词了) + cloning dinosaurs from DNA, but the possibility that doing it is remote and probably impossible. 根据doing it是错误的,应该用doing so,排除掉三个。剩下两个开始纠结 B. cloning dinosaurs from DNA, but the possibility that doing so is remote and probably nonexist.(我认为possibility和probably放在一起比较累赘) D. dinosaurs cloned from DNA, but doing so is remote and impossible.