Find the coordinate of double ordinate for the ellipse $\large\frac{x^2}{a^2}+\large\frac{y^2}{b^2}$$=1$

Question

$\begin{array}{1 1}(a)\;k=\large\frac{b}{a}\normalsize (a^2-h^2),k'=-\large\frac{b}{a}\normalsize (a^2-h^2)\\(b)\;k=\large\frac{b^2}{a}\normalsize (a^2-h^2),k'=-\large\frac{b^2}{a}\normalsize (a^2-2h^2)\\(c)\;k=\large\frac{b}{2a}\normalsize (a^2-h^2),k'=-\large\frac{b}{2a}\normalsize (a^2+h^2)\\(d)\;k=\large\frac{2b}{a}\normalsize (a^2-h^2),k'=-\large\frac{2b}{a}\normalsize (a^2-h^2)\end{array}$