Solve the Problem $z = 49 - x ^ { 2 } - y ^ { 2 }$

Multiple Choice

Solve the problem.
-Find the center of mass of the region of constant density bounded by the paraboloid $z = 49 - x ^ { 2 } - y ^ { 2 }$ and the $x y$ -plane.

A) $\bar { x } = 0 , \bar { y } = 0 , \bar { z } = \frac { 49 } { 3 }$
B) $\bar { x } = 0 , \bar { y } = 0 , \bar { z } = \frac { 49 } { 2 }$
C) $\bar { x } = 0 , \bar { y } = 0 , \bar { z } = \frac { 7 } { 3 }$
D) $\bar { x } = 0 , \bar { y } = 0 , \bar { z } = \frac { 7 } { 2 }$