A train stops at a station. Many people come out to buy food and fruits. A young man wants to come out, but it starts to rain. A boy stands under an umbrella. The young man says to the boy. "Can you go and get us two hamburgers, one for you and one for me? Here are two dollars. Be quick!" "Great!" says the boy and then he goes to buy hamburgers. After some time, the boy is back. He eats a hamburger. "Where is my hamburger?" asks the young man. "Oh, there is only one hamburger left. So I eat my hamburger. Here is your dollar." The boy goes to buy hamburgers for him because he has   _  .
a hamburger an umbrella a raincoat a dollar