[SC悬赏令] 一道prep的指代问题，我想问题目是不是出得不严谨呢？

70. PREP07 的这一题

It isunclear whether chimpanzees are unique among nonhuman species in their ability to learnbehaviors from one another, or if, whenother animals are studied in as much depth, similar patterns would be found. (A) if, when other animals are studied inas much depth, similar patterns would be found (B) if other animals were studied with asmuch depth they would exhibit similar patterns(C) would similar patterns be found inother animals if they were studied in as much depth(D) whether similar patterns would beexhibited in other animals that were studied with as muchdepth(E) whether other animals would exhibitsimilar patterns if they were studied in as much depth

答案是选E，当然，我的疑惑是，题目未划线部分出现了their这个形容词性的代词，明显这个指代了chimpanzees，由于这题这是一个句子，句子中的指代不能有歧义，那么后半部分划线句的E选项，they这个代词指代就不正确了吧，为什么这题还能选E呢，请NN解释一下