If $$\frac{x}{y}{\text{ = }}\frac{{a + 2}}{{a - 2}}{\text{,}}$$then the value of $$\frac{{{x^2} - {y^2}}}{{{x^2} + {y^2}}}$$= ?

• A. $\frac{{2a}}{{{a^2} + 2}}$$
• B. $\frac{{4a}}{{{a^2} + 4}}$$
• C. $\frac{{2a}}{{{a^2} + 4}}$$
• D. $\frac{{4a}}{{{a^2} + 2}}$$