If $$\sqrt{3} \tan \theta = 3 \sin \theta$$, then what is the value of $$\sin^2 \theta - \cos^2 \theta$$?

A

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

B

$$\frac{1}{4}$$

C

$$\frac{1}{2}$$

D

$$\frac{1}{5}$$