What is the value of $$\frac{\cot 60^\circ - \cot 30^\circ}{1 + \cot 60^\circ . \cot 30^\circ}$$?

A

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

B

$$\surd{3}$$

C

$$-\surd{3}$$

D

$$-\frac{1}{\surd{3}}$$