A tank is filled by 3 taps K, L and M with uniform flow. The second tap L takes 3 times the time taken by K to fill the tank, while M takes two times the time taken by L to fill the tank. If all the three taps can fill the tank in 14 hours, find the time required by tap K alone to fill the tank. A) 10hrs B) 21hrs C) 14hrs D) 22hrs