[SC悬赏令] 请问OG17的747题答案是不是给错了呀

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.

              题目贴在这里了，我搜索之前的帖子时，发现在GWD24-41的答案中，正确的选项是C，这道题我就是选择的C，但是OG给的答案是D。我觉得D选项有问题呀，因为在题干中句末的代词用的是its，难道不应该整个句子都统一代词么？

OG中对C的解释：Its being so genetically similar is incorrect because there is no explicit statement of what the ant is similar to.

这应该是对B选项的解释吧，所以这道题目的答案是错误的吧。。

OG对D的解释：The clause with similar uses the plural they and an explicit to each other, and agreement is respected between ants and fellows.

请大神帮忙解释一下，谢谢了。。我感觉这题的解释乱七八糟的。。