At 12:00 noon, Anna and Bill left home and walked in the same direction. Anna walked at 4\:km/h and Bill walked at 3\:km/h. At 12:15 their dog Dexter, running at 6\:km/h, left home to run after them. The dog ran until it caught up to Anna, then it ran back to Bill. (In his excitement, Dexter lost no time in turning around once he reached Anna.) At what time did Bill meet Dexter on Dexter’s way back?
Answer Choices
A. 1:00\:p.m.
B. 1:15\:p.m.
C. 12:45\:p.m.
D. 1:05\:p.m.
E. 12:50\:p.m.