A and B can finish a work together in $$3\frac{2}{3}$$ days. C and D can finish the same work in $$3\frac{1}{7}$$ days. If A, B, C and D do the work together. how long will it take for them to finish half of the work?

A

$$1\frac{1}{13}$$ days

B

$$\frac{8}{13}$$ days

C

$$\frac{2}{13}$$ days

D

$$\frac{11}{13}$$ days