Find the Acceleration of a Particle with the Given Position $\mathbf { r } ( t ) = 9 \sin t \mathbf { i } + 10 t \mathbf { j } - 8 \cos t \mathbf { k }$

Find the acceleration of a particle with the given position function. $\mathbf { r } ( t ) = 9 \sin t \mathbf { i } + 10 t \mathbf { j } - 8 \cos t \mathbf { k }$

A) $\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } - 9 \cos t \mathbf { j }$
B) $\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 9 \cos t \mathbf { j }$
C) $\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 10 \cos t \mathbf { k }$
D) $\mathbf { a } ( t ) = - 9 \sin t \mathbf { i } + 8 \cos t \mathbf { k }$
E) $\mathbf { a } ( t ) = 9 \sin t \mathbf { i } - 10 t \mathbf { k }$