A university bookstore manager is mildly concerned about the number of textbooks that were under-ordered and thus unavailable two days after the beginning of classes. The manager instructs an employee to pick a random number, go to the place where that number book is shelved, examine the next 50 titles, and record how many titles are unavailable. (A) Technically, this process does not yield a random sample of the books in the store. Why not? (B) How could a truly random sample be obtained?