If $$\left(x^{3}+y^{3}\right)^{\frac{2}{3}}=\left(x^{2}+y^{2}\right)$$, then the value of $$\frac{x^{2}+y^{2}}{xy} x \neq 0, y \neq 0$$, is:

A

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

B

1

C

$$x^{2}+y$$

D

$$x+y^{2}$$