Find the Standard Form of the Equation of the Parabola $y ^ { 2 } = 4 x$

Multiple Choice

Find the standard form of the equation of the parabola with the given characteristic(s) and vertex at the origin. ​
Directrix: y = -1
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A) $y ^ { 2 } = 4 x$
B) $x ^ { 2 } = - \frac { y } { 4 }$
C) $x ^ { 2 } = 4 y$
D) $y ^ { 2 } = - 4 x$
E) $x ^ { 2 } = - 4 y$