If $$\sin \theta = \frac{2\sqrt{ab}}{a + b}, a > b > 0$$, then the value of $$\frac{\cos \theta + 1}{\cos \theta - 1}$$ will be :

A

$$-\frac{b}{a}$$

B

$$-\frac{a}{b}$$

C

$$\frac{a}{b}$$

D

$$\frac{b}{a}$$