The central idea of the fourth paragraph (lines 41230-93625) is that-
Here, the idea that is central to the fourth paragraph is that public transportation “can be faster, more comfortable, and cheaper than the private automobile". The rest of the paragraph provides examples of fast and convenient public transportation systems- examples that support this central idea. Here, option B fits into the context. The other options simply state points that the paragraph mentions and does not bring out the main idea of the paragraph.