A customer who came one day to his little bookstore in Philadelphia, not being satisfied with the price demanded by the clerk for the book he wished to purchase, asked for the owner. "Mr. Franklin is very busy just now in the press room," replied the clerk. The man, however, who had already spent an hour aimlessly turning over books, insisted on seeing him. In answer to the clerk's summons, Mr. Franklin hurried out from the newspaper establishment at the back of the store. What is the lowest price vou can take for this book sir asked the leisurely customer. What is a central idea of the selection?

A. Books take time to select.

B. Time is extremely valuable.

C. Clerks are not always right.

D. Everything costs too much money.