请选择ABC7z4E8C3W5`:a(u7n,C3WWe ___ at the airport all morning before there was any news about our flight.6[9_/g;O,D5F/{1~*a.O+x
A. have been waiting6[9_/g;O,D5F/{1~*a.O+x
B. had been waiting6[9_/g;O,D5F/{1~*a.O+x
C. are waiting6[9_/g;O,D5F/{1~*a.O+x