In the argument given , the two highlighted portions play which of the following roles? A. The first sentence introduces the topic of the passage and the last one supports the main idea of the passage. B. The first sentence presents a thesis and the last one further develops the thesis. C. The first sentence summarizes the main idea of the passage and the last one paraphrases it literally. D. The first sentence presents a context for the discussion of the passage and the last one evaluates the discussion. E. The first sentence presents the negative thesis of the passage and the last one presents the positive thesis.