Let $\mathbf { F } ( x , y , z ) = 3 z \mathbf { k }$

Multiple Choice

Let $\mathbf { F } ( x , y , z ) = 3 z \mathbf { k }$ and S is $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } = 9$ . Using the Divergence Theorem, $\iint S$ $\mathbf { F } \bullet \mathbf { n } d S$ is

A) 64 $\pi$
B) 72 $\pi$
C) 84 $\pi$
D) 96 $\pi$
E) $108 \pi$