Context: Polly 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 Polly decides to buy a copy of the book. Which result would be a cost?
A. Polly will get to keep the book as long as she wants.
B. Polly will spend money to buy the book.
From the given choices, pick the correct answer and respond by indicating the letter of the correct option.

B