Find the Standard Form of the Equation of the Ellipse $( \pm 5,0 )$

Find the standard form of the equation of the ellipse with the following characteristics.
Foci: $( \pm 5,0 )$ , major axis of length: 18

A) $\frac { x ^ { 2 } } { 81 } + \frac { y ^ { 2 } } { 56 } = 1$
B) $\frac { x ^ { 2 } } { 81 } + \frac { y ^ { 2 } } { 25 } = 1$
C) $\frac { x ^ { 2 } } { 25 } + \frac { y ^ { 2 } } { 81 } = 1$
D) $\frac { x ^ { 2 } } { 324 } + \frac { y ^ { 2 } } { 25 } = 1$
E) $\frac { x ^ { 2 } } { 324 } + \frac { y ^ { 2 } } { 299 } = 1$