Answer: The correct option is (A) b < 4000.
Step-by-step explanation: Given that the public library has fewer than 4,000 books.
We are to select the inequality that describes the number of books in the library.
The number of books in the library is represented by b.
According to the given information, the inequality hat describes the number of books in the library is given by

Thus, (A) is the correct option.