Which expression is a factor of this polynomial?
$x^3+2x^2-9x-18$
A$(x-2)$
B$(x+1)$
C$(x-6)$
D$(x+2)$
$x^3+2x^2-9x-18$
A$(x-2)$
B$(x+1)$
C$(x-6)$
D$(x+2)$