Grayson's has been in the publishing business for fifty years. In the past two years, the company has noticed that book sales have been tapering off, as more and more readers prefer formats they can read on e-readers or smartphones. Grayson's needs to analyze the changes in the environment so that it can change its business strategies and meet the needs of the new market. It commissions a market research firm to collect information about the recent changes in reading habits. Which of the following questions is the most irrelevant for this purpose?
A.
How much do readers spend on e-books in a month?
B.
Which format is more reader-friendly, e-books or traditional books?
C.
How many books does an individual customer buy in a month?
D.
What types of books do customers buy in traditional form?