Passage Four
One evening Mr. Green was driving home along a lonely country road. He had ￡ 100.00 in his pock et. At the loneliest part of the road, a man asked for a lift (搭车). Mr. Green told him to get into the car and continued his driving. When he talked to the man and learned that the man had been in prison for robbery and had broken out of prison two days before, Mr. Green was very worried.
Suddenly he saw a police-car and had a bright idea. He just reached a small town where the speed limit (限制速度) was 30 miles an hour. But he drove the car as fast as it could go. He looked back and saw that the police-car had begun to chase (追) him. After a mile or so the police-car overtook (赶上) him and ordered him to stop. A policeman got out and came to Mr. Green's car. Mr. Green hoped that he could tell the policeman about the escaped robber, but he felt the man had put a gun against his back. The policeman took out his notebook and pencil, saying he wanted Mr. Green's name and address. Mr. Green asked to be taken to the police station, but the policeman said, "No, you will have to appear at the police station later." Mr. Green had to do as the policeman told him. The policeman wrote his name and address down, put his notebook and pencil back in his pocket and gave Mr. Green a talk about dangerous driving. Then Mr. Green started up his car again and drove on.
Just as he reached the outskirts (郊区) of London, the passenger said, "! want to get off here." Mr. Green stopped the car, the man got out and said, "Thanks for the lift. You've been good to me. This is the least I can do in return (报答)." And he handed Mr. Green the policeman's notebook, which he stole while the policeman was talking to Mr. Green.
46. The man asking for a lift was ______.

A. a robber who robs drivers
B. a policeman who had worked in prison
C. a prisoner who had escaped from prison
D. a stranger with ￡ 100.00 in his pocket