Find the value of $$\frac{\cos^{2}15^{\circ} - \sin^{2}15^{\circ}}{\cos^{2}145^{\circ} + \sin^{2}145^{\circ}}$$

A

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

B

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

C

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

D

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