B
Policeman(男警察): Hello!
Marcus: Hello! I lost my bag(包)this morning.
Policeman: What color is your bag?
Marcus: It's black.
Policeman: We have two bags here.Is this your bag?
Marcus: No, it isn't.
Policeman: Is that your bag?
Marcus: Yes! That's my bag!
Policeman: What's in your bag?
Marcus: My keys, my book, my green pen ... Oh, and my white phone.
Policeman: What's your name?
Marcus: Mr. Smith.
Policeman: What's your first name,Mr. Smith?
Marcus: Marcus.
Policeman: Yes,it's your bag.Here you are.
Marcus: Thank you.
根据材料内容选择最佳答案。