阅读下列短文，从短文后各题所给的A、B、C、D四个选项中，选出可以填入空白处的最佳选项。

An old man sat on a train. He was on his way home after he 1 his son working in a big city. He was looking at the new shoes happily because his son bought them for him. Suddenly, one of the shoes fell out of the window of the 2 by accident. The people around him all were 3 for him and they said to him, "Don't worry! It's only a shoe. You still have a shoe." But to their surprise, the old man threw the other 4 out of the window. A woman asked, "Why? It's new." The old man said with a smile, "Only one shoe is no use for me. But if anyone finds that pair of shoes, he can 5 them happily."