Pipe C can fill a tank in 12 hours and pipe D can fill the same tank in 40 hours. In how many hours both pipe C and D together can fill the same tank?

A

$$\frac{60}{7}  hours$$

B

$$\frac{60}{11}  hours$$

C

$$\frac{120}{13}  hours$$

D

$$\frac{120}{11}  hours$$