If a and b are two non-zero unequal numbers, then
$$\frac{(a-b)(\sqrt{a} - \sqrt{b})}{(a + b)(\sqrt{a} + \sqrt{b})}$$

A

$$1 - 2 \sqrt{\frac{1}{a} + \frac{1}{b}}$$

B

$$1 + 2 \sqrt{\frac{1}{a} + \frac{1}{b}}$$

C

$$1 - 2 \frac{\sqrt{ab}}{a+b}$$

D

$$1 + 2 \frac{\sqrt{ab}}{a+b}$$