Context: Harper is deciding whether to buy a copy of a book or borrow it from the library. She would like to be able to keep the book as long as she wants, but buying the book would cost money. She could borrow the book for free, but she would have to return it in a few weeks.
Suppose Harper decides to borrow the book from the library. Which result would be a cost?
A. Harper will give up the chance to keep the book as long as she wants.
B. Harper will save some money by not buying the book.
From the given choices, choose the correct answer and respond with the letter of that choice.

A