A and B alone take 4 and 6 hours, respectively, to complete a certain work. If they work alternatively each hour, starting with A first, how long will it take them to complete the work?

A

$$\frac{14}{3}$$ hours

B

$$\frac{17}{3}$$ hours

C

$$\frac{11}{3}$$ hours

D

$$\frac{13}{3}$$ hours