请教一题

GWD-24-41.

In California, a lack of genetic variation in the Argentine ant has allowed the species to spread widely; due to their being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits the spread of this species in its native Argentina.

A.    due to their being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits

B.    due to its being so genetically similar the ant considers all its fellows to be a close relative and thus does not engage in the kind of fierce intercolony struggles that limit

C.    because it is so genetically similar, the ant considers all its fellows to be close relatives and thus does not engage in the kind of fierce intercolony struggles that limits

D.    because they are so genetically similar to one another, the ants consider all their fellows to be close relatives and thus do not engage in the kind of fierce intercolony struggles that limit

E.     because of being so genetically similar to one another, the ants consider all their fellows to be a close relative and thus do not engage in the kind of fierce intercolony struggles that limits

答案C

但C选项中最后的that应该是修饰struggles的，为什么limit用单数阿？

长久以来的争议题.选C，D的都有.

关于the kind of + pl. noun结构后面的谓语动词是单数还是复数是个争议了百年的话题了,现在判断的关键在于视kind为中心词，还是视struggles为中心词，甚至很多时候都能够换用.GMAT过去的题目也没有做出过表态到底后面谓语动词应该用什么(即使表态了可能也不能说明问题，因为可能只是根据该道题目逻辑意思判断中心词，对别的题目不一定适用).个人觉得在这里应该视struggles为中心词.因为如果视the kind为中心词，那么前面必然有关于which kind的明确说明，让the kind有所指.所以the kind应该只是做形容词修饰struggles，即后面应该用limit。

其次,it is so genetically similar的表达是不清楚的.similar to who/what?，it既然指代the ant那个种群,那么应该是这个种群跟别的种群或别的事物similar，而不是表达了种群内部个体的相似. 再者，既然是把内部个体当作分析对象，那么就应该不应该把这个种群视作整体，而应该视作不同个体.

故我支持D。