Find the equation of normal for the hyperbola $\large\frac{x^2}{a^2}-\frac{y^2}{b^2}$$=1$ in parametric form?

Question

$\begin{array}{1 1}(a)\;\large\frac{by}{\tan \theta}+\frac{ax}{\sec\theta}\normalsize =a^2+b^2\\(b)\;\large\frac{by}{\tan \theta}-\frac{ax}{\sec\theta}\normalsize =a^2+b^2\\(c)\;\large\frac{by}{\tan \theta}+\frac{ax}{\sec\theta}\normalsize =a^2-b^2\\(d)\;\text{None of these}\end{array}$