The Surface Integral $\int \int$ S $z d S$ Where S Is $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } \leq 4 , z \geq 0$

Multiple Choice

The surface integral $\int \int$ S $z d S$ where S is $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } \leq 4 , z \geq 0$ is

A) $- 8 \pi$
B) $8 \pi$
C) $6 \pi$
D) $- 6 \pi$
E) $4 \pi$