D
Compared to us, people who lived a century ago had very few diversions to amuse them. Ttherefore, they likely read much more than we do today. Which one of the following statements, if true, most weakens the argument?
A: Many of the books published a century ago were of low literary quality.
B: The number of books sold today is larger than it was a century ago.
C: One of the popular diversions of a century ago was horse racing.
D: On average, people who lived a century ago had considerably less leisure time than we do today.