Considering the situation that "Penny thinks the price of books will decrease next week" thus, the statement that reflects how Penny's behavior will change in response to her expectations is "Penny's demand for books today will decrease."
If the price of books would be reduced next week, Penny would prefer to buy more books at a lower cost, thereby wait till next week to purchase books.
Therefore, Penny's demands for books today would reduce, while he waits till next week to buy more books.
This situation follows the law of demands which state the lower the price, the higher the market, and vice versa.
Hence, in this case, it is concluded that the correct answer is option D. "Penny's demand for books today will decrease."
Learn more about the law of demand here: https://brainly.com/question/19151286
