The correct option is D Constant function
Polynomial function is of the form:
f(x)=a0+a1x+a2x2+...+anxn
When n=0, we get f(x)=a0, a constant function.
When n=1, we get f(x)=a0+a1x, a linear function.
When n=1, we get f(x)=a0+a1x+a2x2, a quadratic function.
But, the modulus function is of the form
f(x)=a|x−h|+k, and hence not a polynomial function.