A、He received a call from the delegation. B、He discussed with the Poland delegation. C、He knew it through the contract they sign

M: Come in．Rose．Coffee?
W: Thank you．Jack．
M: How about the visit by the delegation from Poland?
W: Well．I still don’t get it．Do we know when they are coming?
M: We offered them 3 choices．The end of March,the middle of April and the beginning of May．
W: Yeah．
M: And they chose the earliest one,which is good because we are rather busy in May．
W: True. But we do need definite dates of their coming and how many are coming. There were six of them last time. Did they say eight this time? My assistant needs to make a firm booking for their accommodations now. Otherwise it will be very difficult to find a hotel.
M: You are right. They said six to eight originally, but we got an E-mail this morning, saying it is going to he seven. Now we’ve got the definite number, we can make all the other bookings for them.
W: Good. That gives us eight weeks until they come.
M: Right. Here are my suggestions for their schedule. They will be with the university for five days. On the first day, I think they should visit our campus. The second day we can show them around the downtown. This will give them a general picture of the changes in today’s China. And the last three days are for discussion and seminars.
W: OK. Do we need to invite some other famous professors from other universities?
M: That’s a good idea. But no more than five are needed.
W: Right. I will arrange that.