If $$\frac{x^2}{a^2}+\frac{y^2}{b^2}-\frac{z^2}{c^2}$$ and $$\frac{\sin\alpha}{\sin\beta}=b$$ then the value of $$\sin^{2}\beta$$ in trems of a and b is

A

$$\frac{a^{2}+1}{a^{2}-b^{2}}$$

B

$$\frac{a^{2}-b^{2}}{a^2+b^2}$$

C

$$\frac{a^2-1}{a^2-b^2}$$

D

$$\frac{a^2-1}{a^2+b^2}$$