What is the quadratic regression equation that fits these data?
x: -4, -3, -2, -1, 0, 1, 2, 3, 4
y: 42, 30, 20, 13, 8, 13, 20, 32, 54.
a) y = 3x² + 2x + 1
b) y = -x² + 5x + 8
c) y = -2x² + 3x + 5
d) y = x² + 3x + 5