The writer first describes two opposing viewpoints and says "the historical reality is not reducible to one or the other."

So we get the sense that the purpose of the passage is not to highlight a flaw in or support either one of the viewpoints.

Then in the second paragraph the writer goes on to describe what he or she believes was the historical context.

While in a sense the historical context described seems to lean toward supporting one viewpoint over the other, the writer has not made a point of specifically identifying a flawed assumption upon which is based one of the viewpoints.

So A is the best answer.