Answer: 2 “From the first edition in 1812/1815 to the final one in 1857…”
The main purpose of the paragraph is to provide a description of how the Grimm Brothers gathered their stories and how they decided which ones to include in their books.
The last sentence is the one that fully explains this process and adds key details. It claims that the brothers received lots of contributions from different people, which they acknowledged in various ways. However, options 1, 3, 4 and 5 only provide a specific example of this pattern, instead of providing more details regarding the main idea of the paragraph. Any one of them could be removed without significantly affecting the rest of the text.