听力原文：My friend, David kept birds. He loves his birds very much. One day he phoned me,

听力原文： My friend, David kept birds. He loves his birds very much. One day he phoned me, and told me that he was going away for a week. He asked me to feed the birds for him and said that he would leave the key to his front door in my mailbox. Unfortunately, I forgot all about the birds until the night before David was going to return. What was worse, it was already dark when I arrived at his house. I soon found the key David gave me could not unlock either the front door or the back door. I was getting hopeless. I kept thinking of what David would say when he came back. I was just going to give up when I noticed that one bedroom window was slightly open. I'm very happy. I found a stone and pushed it under the window. As the stone was very heavy, I made a lot of noise. But in the end, I man- aged to climb up and open the window. I actually had 'one leg inside the bedroom when I suddenly realized that someone was shining a flashlight up at me. I looked down and saw a policeman and an out lady, one of David's neighbors. "What are you doing up there？" asked the policeman. Feeling like a complete fool, I replied, "I was just going to feed Mr. David's birds. "But I don't think they can believe me.

Who is the speaker？

A．A policeman.

B．David's neighbor.

C．David's friend.