根据短文内容，选择正确答案。
B
    A young man and an old man were waiting for a train at a station. They sat next to each other.
    "What's in your bag?” as ked the young man. “Gold,” answered the old man,“nothing but gold."
    The young man could hardly believe his ears. “What?” he said to himself in surprise. Then he began to think how to get the gold from the old man.
    The old man looked tired and sleepy and it seemed that he could hardly keep his eyes open. So the old man lay down and before long he fell asleep.
    The young man ran away with the old man's bag as quickly as he could. Then he stopped and quickly opened the bag. There was nothing but a lot of small stones in the bag!