Find the Equation of the Ellipse with Vertices At $(-20,0)$ And $(20,0)$

Multiple Choice

Find the equation of the ellipse with vertices at $(-20,0)$ and $(20,0)$ and foci at $(15,0)$ and $(-15,0)$ .

A) $\frac{x^{2}}{400}+\frac{y^{2}}{175}=1$
B) $\frac{x^{2}}{175}+\frac{y^{2}}{400}=1$
C) $\frac{x^{2}}{400}+\frac{y^{2}}{225}=1$
D) $\frac{x^{2}}{225}+\frac{y^{2}}{400}=1$