Write an Equation for the Parabola with Vertex at the Origin

Multiple Choice

Write an equation for the parabola with vertex at the origin.
-Focus $( 0,7 )$

A) $y ^ { 2 } = 7 x$
B) $x ^ { 2 } = 28 y$
C) $y ^ { 2 } = 28 x$
D) $x ^ { 2 } = 7 y$