单项选择题

A: What time is this meeting supposed to begin
B: I’m not sure. I thought it was to start at 7:00 p.m., but it’s already 7:20 p.m..
A: ______
B: It’s unlikely that the guest speaker has arrived yet. I think he is still eating his dinner.
A: Well, that explains it!

A. What do you think the problem is
B. Don’t you know
C. Are you sure
D. What do we do then