Find the equation for the ellipse that satisfies the given conditions : Foci $(\pm 3, 0), a = 4$

Question

$\begin {array} {1 1} (A)\;\large\frac{x^2}{16}+\large\frac{y^2}{7}=1 & \quad (B)\;\large\frac{x^2}{7}+\large\frac{y^2}{16}=1 \\ (C)\;\large\frac{x^2}{16}-\large\frac{y^2}{7}=1 & \quad (D)\;\large\frac{x^2}{7}-\large\frac{y^2}{16}=1 \end {array}$