Answer:
D.) Despite the differences between Americans, their ability to unify is unique and
noteworthy
Step-by-step explanation:
In this article, Anna Quindlen claims that America is unique country. There are people of many nations, cultures, races and religions, but all of them can get along with each other even if their nations or religions are at war. Of course, this can be regarded as over - idealised point of view, but she states it's true, especially when facing a major threat (she gives example of the 9/11 terrorist attack).
So, with this in mind, we could say that that the correct option is D.