A pipe can fill a tank in 4 hours and a leak at the bottom can empty that full tank in 6 hours. If after the tank is $$\frac{1}{3}$$ full, the leak is completely closed, how much time from beginning will it take for the tank to get filled completely?

A

12 hours

B

4 hours

C

9 hours

D

$$\frac{20}{3}$$ hours