There are far fewer independent bookstores than there were 20 years ago, largely because chain bookstores prospered and multiplied during that time. Thus, chain bookstores succes has been to the detriment of book consumers, for the shortage of independent bookstores has prevented the variety of readily available books from growing as much as it otherwise would have.
Which one of the following is an assumption on which the argument relies?
a) book consumers would be better off if there were a greater variety of readily availble books than there currently is
b) independent bookstores typically do not sell the kind of books that are available in chain bookstors
c) the average bookstore today is larger than the average bookstore of 20 years ago.
d) the average bookstore today is smaller than the average bookstore of 20 years ago.
e) some book consumers value low prices more highly than wide selection