Give the Focus, Directrix, and Axis for the Parabola

Multiple Choice

Give the focus, directrix, and axis for the parabola.
-A domed ceiling is a parabolic surface. For the best lighting on the floor, a light source is to be placed at the focus of the surface. If 10 m down from the top of the dome the ceiling is 19 m wide,
Find the best location for the light source.

A) 9 m down from the top
B) 4.6 m down from the top
C) 2.3 m down from the top
D) 6.9 m down from the top