ITMC 2018 Grade 9 National Preliminary set01 Question 19

Question 19

The parabola $y=ax^2+bx+c$ has vertex $(20,18)$ and passes through the origin. Which point is not on it?

$(10,13.5)$
$(-10,-22.5)$
$(30,13.5)$
$(-30,-22.5)$
Insufficient information.