An arch is in the shape of a parabola with a span of 21 feet and a maximum height of 12 feet. Assuming that the point on the ground below the highest point of the arch is represented by the point (0,0), which of the following gives the equation of the parabola that can be used to model the arch? Select the correct answer below:

x2=−14716(y−12)

y2=−84(x−12)

(y−12)2=−12x

x2=−21(y−12)