Tl1e value of $$3\frac{6}{7}\div5\frac{1}{7}\times3\frac{1}{2}\div5\frac{1}{4}$$ is:

A

$$\frac{1}{5}$$

B

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

C

$$\frac{1}{7}$$

D

$$\frac{3}{7}$$