单选题 Two cars left the same town traveling in the same direction. Car A traveled 40 miles per hour and left at 3:20. Car B traveled 50 miles per hour and left at 4:40. At what time will car B catch up with car A?
(A) 10:00 (B) 9:00 (C) 8:40
(D) 7:20 (E) 6:10