Let $f(x)=4 x^{2}-4 a x+a^{2}-2 a+2$ and the global minimum value of $f(x)$ for $x \in[0,2]$ is equal to 3 .
The values of a for which $f(x)$ is monotonic for $x \in[0,2]$ are
(A) $a \leq 0$ or a $\geq 4$
(B) $0 \leq a \leq 4$
(C) $a>0$
(D) None of these