Which system of equations is represented by the graph?

one parabola opening upwards and one parabola opening downwards intersecting at points (3, 9) and (-3, 9)

y = x2 + 3x

y = –x2 + x + 18
y = x2

y = –x2 +18
y = x2

y = x2 + 18
y = x2

y = –x2 – x – 18