Solve the Problem $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } = 4$

Solve the problem.
-The shape and density of a thin shell are indicated below. Find the coordinates of the center of mass.
Shell: portion of the sphere $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } = 4$ that lies in the first octant
Density: constant

A) $\left( \frac { 1 } { 2 } , \frac { 1 } { 2 } , \frac { 1 } { 2 } \right)$
B) $\left( \frac { 2 } { 3 } , \frac { 2 } { 3 } , \frac { 2 } { 3 } \right)$
C) $( 1,1,1 )$
D) $( 2,2,2 )$