Speaker A: Good afternoon, Im here for my four oclock appointment with Dr. Brown. Speaker

Speaker A: Good afternoon, Im here for my four oclock appointment with Dr. Brown. Speaker B: ______

A．Nice to see you. I"m Dr. Brown"s secretary.

B．Why don"t you have a seat for a moment？

C．Excuse me, when did you make this appointment with him？

D．I"m sorry. He will be busy the whole afternoon.

请帮忙给出正确答案和分析，谢谢！