GMAT Sentence Correction (SC) | Re: In California, a lack of genetic variation in the Argentine

However, I selected the right choice. I just want to know the reason of rejecting choice B.

It seems that usage of "being" is incorrect in choice b. Correct me if I am wrong.

1. If a choice were below, would it be correct? In other words, usage of singular form of the ANT will be correct in this sentence?

because it is so genetically similar to one another,the ant considers all its fellows to be a close relative and thus does not engage in the kind of fierce intercolony struggles
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