The value of $$25 \div 15 of 4 \times [4 \div 5 \times (9 - 7)] - (20 \div 5 of 9)$$ is:

A

$$\frac{2}{3}$$

B

$$\frac{1}{3}$$

C

$$\frac{2}{9}$$

D

$$\frac{4}{9}$$