Answer:
C: h, f, g
Explanation:
The axis of symmetry of the standard form quadratic y=ax²+bx+c is given by the equation x=-b/(2a).
__
The axes of symmetry for your functions are ...
f: x = -(-8)/(2(2)) = 8/4 = 2
g: x = -(-6)/(2(1)) = 6/2 = 3
h: x = -0/(2(-2)) = 0/4 = 0
From least to greatest, the order is h(x), f(x), g(x).
_____
Additional comment
The axis of symmetry is the vertical line through the vertex (minimum or maximum).