Answer choice B, the second-to-last sentence in the passage, best summarizes the main point of the passage: that although The Five mightn't have had solid formal training, they influenced Russian music, and that influence extended beyond their own era. Answer choice A is too specific, and focuses on those who influenced rather than on the actual composers who made up The Five. Because it is the opening sentence of the passage, answer choice C is a good option. However, answer choice B get more to the heart of the topic. Answer choice C leaves out the formation about long-term influences, so it is not the best option for a summary sentence. Answer choice D focuses on only two of The Five, so it cannot be a summary statement for the entire passage.