For her birthday, Kendra received a gift card in the mail from her grandparents. The gift card was worth $50. Kendra thought, since she had just received other gifts for her birthday, she would wait a while to spend the gift card. Unfortunately, Kendra forgot all about the gift card, and the card loses $5 every month after its date of purchase if it has not been used.
If Kendra forgot the card for three months, she lost $______.

a) 9 b) 10 c) 15 d) 12