阅读下列短文，从每题所给的四个选项中选出最佳选项。

Mary wanted to buy a birthday present for her mother, but she had only ten yuan in her pocket. She walked along the street and looked at many shops, but everything there was too expensive for her. At last she went into a small flower shop. The owner was a kind old woman. When she heard Mary's story, she gave Mary a beautiful carnation for only five yuan. Mary was very happy and ran home with the flower in her hand. Her mother said it was the best gift she had ever received.

1. How much did Mary pay for the gift?