Read the following conversation and answer the question.

M: Hi, Mum.

W: There you are. I'm getting worried. It's so late.

M: Yes. I ran into Linda and we went to a pub. She told me a funny thing.

W: Oh? What was that?

M: Well, she was driving home after work, and she suddenly saw an old lady on her hands and knees in the middle of the road.

W: Really?

M: Yes, Linda was so shocked that she stopped suddenly and the car behind crashed into hers.

W: Was her hurt?

M: No.

W: And what was the old lady doing?

M: I am just coming to that. So Linda got out of her car and saw the old lady pick up something and walk away.

W: Lucky indeed. Linda didn't run her over.

M: Then a policeman came. But he didn't believe what Linda said.

W: Well...

M: Luckily there was a witness, a man waiting for a bus. He saw it all. Guess what the old lady was doing?

W: I haven't the slightest idea.

M: She was looking for her gold tooth.

W: A gold tooth?

M: Yes, it fell out as she was crossing the road. The witness heard her saying, "Oh, my gold tooth..."

Question: Where was the witness? 

- Outside the pub.

- At a bus stop.

- In his car.


At a bus stop.