Find the mean proportion of $$\frac{a^{2} + b^{2}}{a - b}$$ and $$\frac{a^{2} - b^{2}}{a^{2} - ab + b^{2}}$$

A

1

B

a + b

C

$$\frac{a + b}{a - b}$$

D

$$\sqrt{a + b}$$