The correct answer is b. by listing step-by-step the time-consuming process that had to be done in order to print just one copy of text prior to the invention of the printing press.
This section illustrates how labor-intensive and inefficient the process of creating books was before Gutenberg's invention. By detailing the roles of scribes, rubicators, and illuminators, it emphasizes the drastic change in book production introduced by the printing press, thus supporting the main idea of the text that highlights the revolutionary impact of Gutenberg’s invention on European culture and the accessibility of knowledge.