The correct answer is: by giving us details that show how exceptional the printing press is.
The part labeled "Books Before the Printing Press" provides information about the difficulties and limitations of book production before the invention of the printing press. This helps to highlight the significance and advantages of Gutenberg's invention, demonstrating how the printing press revolutionized the production and distribution of books. Therefore, it supports the main idea of the text by showcasing the exceptional nature of the printing press.