Tap A and B take 6 hours and 8 hours respectively to fill an empty tank and another tap C empties the full tank in $$x$$ hours. Due to a problem, tap C could not be closed. If it took 12 hour for them to fill the tank, then the value of $$x$$ is

A

4

B

$$4\frac{1}{2}$$

C

$$4\frac{3}{4}$$

D

$$4\frac{5}{4}$$