Find the Standard Form of the Equation of the Parabola $y ^ { 2 } = - 16 x$

Multiple Choice

Find the standard form of the equation of the parabola with the given characteristic(s) and vertex at the origin. ​
Directrix: x = -4
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A) $y ^ { 2 } = - 16 x$
B) $y ^ { 2 } = 16 x$
C) $x ^ { 2 } = - 16 y$
D) $x ^ { 2 } = 16 y$
E) $y ^ { 2 } = \frac { x } { 16 }$