$\text { For the curve } r ( t ) \text {, write the acceleration in the form aTT } + \text { anN. }$

Multiple Choice

$\text { For the curve } r ( t ) \text {, write the acceleration in the form aTT } + \text { anN. }$
-r(t) = (6t sin t + 6 cos t) i + (6t cos t - 6 sin t) j + 3k

A) $a = 6 T + 6 t N$
B) $a = \frac { 1 } { 6 t } N$
C) $a = 6 T + \frac { 1 } { 6 t } N$
D) $a = 6 \mathrm { t }$