Answer:
The author gives supporting details first and concludes with the main idea.
Step-by-step explanation:
The paragraph you were given is the following:
What compelled the Grimms to concentrate on old German epics, tales, and literature was a belief that the most natural and pure forms of culture—those which held the community together—were linguistic and based in history. According to them, modern literature, even though it might be remarkably rich, was artificial and thus could not express the genuine essence of Volk culture that emanated naturally from experience and bound the people together. Therefore, all their efforts went toward uncovering stories from the past.
In this paragraph, the author gives supporting details first and concludes with the main idea.
The main idea of a text is the main point the author is making. Supporting details are facts, statements, and examples that clarify, explain, describe, expand, or illustrate the main idea.
The main idea of the given paragraph is that the Grimm brothers focused on uncovering stories from the past. The previous statements explain why they did that - because they believed that the most natural and pure forms of culture were linguistic and based in history.
This is why the second option is the correct one.