Two pipes 'A' and 'B' can fill a tank in 6 hours and 8 hours respectively and pipe C can empty the full tank in 12 hours. If all the three pipes were opened for 2 hours, what part of the tank is filled?

A

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

B

$$\frac{5}{12}$$

C

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

D

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