The value of $$31\frac{2}{5} \div \left[168 \div \frac{3}{7} of 28 + \left(33 \div \frac{5}{2}\right) + \left(7\frac{3}{5} - 3\frac{2}{5}\right)\right]$$ is:

A

5

B

1

C

3

D

10