The function $f(x)=x^{4}-4 x^{3}+6 x^{2}-4 x+1$ has a
(A) Maxima at $x=0$
(B) Minima at $x=0$
(C) Maxima at $x=1$
(D) Minima at $x=1$
The function $f(x)=x^{4}-4 x^{3}+6 x^{2}-4 x+1$ has a
(A) Maxima at $x=0$
(B) Minima at $x=0$
(C) Maxima at $x=1$
(D) Minima at $x=1$