If sin $$17^\circ$$=$$\frac{x}{y}$$ then the value of $$sec 17^\circ-sin 73^\circ$$

A

$$\frac{y^{2}-x^{2}}{xy}$$

B

$$\frac{x^{2}}{y^{2}-x^{2}}$$

C

$$\frac{x^{2}}{y \sqrt{y^{2}+x^{2}}}$$

D

$$\frac{x^{2}}{y \sqrt{y^{2}-x^{2}}}$$