If $$x = \frac{\sqrt{5} - \sqrt{4}}{\sqrt{5} + \sqrt{4}}$$ and $$y = \frac{\sqrt{5} + \sqrt{4}}{\sqrt{5} - \sqrt{4}}$$ then the value of $$\frac{x^{2} - xy + y^{2}}{x^{2} + xy + y^{2}} =$$?

A

$$\frac{361}{363}$$

B

$$\frac{341}{343}$$

C

$$\frac{384}{387}$$

D

$$\frac{321}{323}$$