Before the printing press, books could be purchased only in expensive manuscript copies. The printing press produced books that were significantly less expensive than the manuscript editions. The public' s demand for printed books in the first years after the invention of the printing press was many times greater than demand had been for manuscript copies. This increase demonstrates that there was a dramatic jump in the number of people who learned how to read in the years after publishers first started producing books on the printing press. Which one of the following statements, if true, casts doubt on the argument? ['Books that were printed on the printing press in the first years after its invention often circulated among friends in informal reading clubs or libraries.', 'During the first years after the invention of the printing press, letter writing by people who wrote without the assistance of scribes or clerks exhibited a dramatic increase.', 'The first printed books published after the invention of the printing press would have been useless to illiterate people, since the books had virtually no illustrations.', 'In the first years after the printing press was invented, printed books were purchased primarily by people who had always bought and read expensive manuscripts but could afford a greater number of printed books for the same money.']