If $e_1$ and $e_2$ are the eccentricities of the hyperbolas $\large\frac{x^2}{a^2}-\frac{y^2}{b^2}$$=1$ and $\large\frac{y^2}{b^2}-\frac{x^2}{a^2}$$=1$ Then value of $\large\frac{1}{e_1^2}+\frac{1}{e_2^2}$ is

Question

$\begin{array}{1 1}(A)\; \bigg|\large\frac{a+b}{a-b}\bigg| \\(B)\; \bigg| \large\frac{a^2-b^2}{a^2} \bigg| \\(C)\;1 \\(D)\;\text{none of these} \end{array}$