A)16
B)0
C)5
D)25
E)4

Multiple Choice

$\text { Find } a _ { \mathbf { N } } \text { at time } t = \frac { \pi } { 3 } \text { for the space curve } \mathbf { r } ( t ) = 4 \cos t \mathbf { i } + 4 \sin t \mathbf { j } + 5 t \mathbf { k }$

A) 16
B) 0
C) 5
D) 25
E) 4