Find the Inflection Point(s) of the Function $f(x)=x^{3}-9 x^{2}+15 x+8$
A)

Find the inflection point(s) of the function $f(x) =x^{3}-9 x^{2}+15 x+8$ .

A) $(0,8)$
B) $(-3,-145)$
C) $(3,-1)$ and $(-3,-145)$
D) $(3,-1)$