Let $f ( x ) = \frac { 1 } { 4 } x ^ { 4 } - \frac { 3 } { 2 } x ^ { 2 } + 8$

Multiple Choice

Let $f ( x ) = \frac { 1 } { 4 } x ^ { 4 } - \frac { 3 } { 2 } x ^ { 2 } + 8$ Then ƒ has a point of inflection at x =

A) $\pm \frac { 1 } { 2 }$
B) $\pm 1$
C) $\pm \frac { 1 } { 3 }$
D) $\pm \frac { 3 } { 2 }$
E) $\pm \frac { 5 } { 2 }$