Let $f ( x ) = x ^ { 4 } - 4 x ^ { 3 } + 16 x$

Multiple Choice

Let $f ( x ) = x ^ { 4 } - 4 x ^ { 3 } + 16 x$ Then ƒ has a relative minimum at x =

A) -2
B) -1
C) 0
D) 1
E) 2