Speaker A: I'm going to the park with some friends for a barbecue on Sunday. Would you like to join us? Speaker B: ______ A.Why not on Saturday? You see, I have an important appointment on Sunday. B.Thanks, but unfortunately I have to take my sister to the airport on Sunday. C.That's a wonderful idea. Barbecue is one of my favorites. D.What preparation do you expect me to do for the barbecue?