Many readers, I suspect, will take the title ... ...

Which one of the following sentences would best complete the last paragraph of the passage?
(A) An understanding of how we categorize is central to any understanding of how we think and how we function, and therefore central to an understanding of what makes us human.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Press: Set D - The Three Step Method