Find the Standard-Form Equation for an Ellipse Which Satisfies the Given

Multiple Choice

Find the standard-form equation for an ellipse which satisfies the given conditions.
-An ellipse centered at the origin having focus $( \sqrt { 77 } , 0 )$ and directrix $x = \frac { 81 } { \sqrt { 77 } }$

A) $\frac { x ^ { 2 } } { 81 } + \frac { y ^ { 2 } } { 4 } = 1$
B) $\frac { x ^ { 2 } } { 81 } + y ^ { 2 } = 1$
C) $\frac { x ^ { 2 } } { 4 } + \frac { y ^ { 2 } } { 81 } = 1$
D) $\frac { x ^ { 2 } } { 9 } + \frac { y ^ { 2 } } { 2 } = 1$