Answer
A.The author starts with the main idea and gives evidence to support it.
Explanation
The author's main idea was that the Grimms were concentrating in old German epics, tales and literature because they believed that the most natural and pure forms of culture which hold a community are in linguistic and contained in history.
The author further explained the idea by showing how modern culture can not express the genuine understanding of Volk culture that started naturally from experience and brought people together.