Two pipes can fill a tank in 6 hours and 8 hours respectively while a third pipe empties the full tank in 12 hours. If all the three pipes operate simultaneously, in how much time will the tank be filled?

• A. 7(1/2) hrs
• B. 4(4/5) hrs
• C. 3 (2/7) hrs
• D. 1(1/5) hrs