For uniformly accelerated motion,
\(v^2=u^2+2 a s\)
\(\quad \downarrow\)
Constant
or
\(s=ut+\frac{1}{2} a t^2\)
\(\quad \downarrow\)
Constant
\(x=\frac{1}{2} a t^2+u t\)
Or the maximum power of \(t\) has to be two.
So, \(4\).
$OA, \,AB,\, BC,\, CD$