Codex Berinensis, a Florentine copy of an ancient Roman medical treatise, is undated but contains clues to when it was produced. Its first 80 pages are by a single copyist, but the remaining 20 pages are by three different copyists, which indicates some significant disruption. Since a letter in handwriting identified as that of the fourth copyist mentions a plague that killed many people in Florence in 1148, Codex Berinensis was probably produced in that year. Which of the following, if true, most strongly supports the hypothesis that Codex Berinensis was produced in 1148? ['According to the account by the fourth copyist, the plague went on for 10 months.', 'A scribe would be able to copy a page of text the size and style of Codex Berinensis in a day.', 'There was only one outbreak of plague in Florence in the 1100s.', 'Other than Codex Berinensis, there are no known samples of the handwriting of the first three copyists.']