Find the Length of the Indicated Portion of the Curve $\mathbf { r } ( t ) = ( 4 \cos t ) \mathbf { i } + ( 4 \sin t ) \mathbf { j } + 5 t \mathbf { k } , 0 \leq t \leq \pi / 2$

Multiple Choice

Find the length of the indicated portion of the curve.
- $\mathbf { r } ( t ) = ( 4 \cos t ) \mathbf { i } + ( 4 \sin t ) \mathbf { j } + 5 t \mathbf { k } , 0 \leq t \leq \pi / 2$

A) $\frac { 3 t } { 2 } \pi$
B) $\frac { \sqrt { 41 } t } { 2 } \pi$
C) $\frac { \sqrt { 57 } \mathrm { t } } { 2 } \pi$
D) $\frac { \sqrt { 41 } t } { 4 } \pi$