Solve the Problem $\delta ( x , y , z ) = \frac { 1 } { 81 - x ^ { 2 } - y ^ { 2 } }$

Multiple Choice

Solve the problem.
-Find the mass of the region of density $\delta ( x , y , z ) = \frac { 1 } { 81 - x ^ { 2 } - y ^ { 2 } }$ bounded by the paraboloid $z = 81 - x ^ { 2 } - y ^ { 2 }$ and the $x y$ -plane.

A) $6561 \pi$
B) $729 \pi$
C) $9 \pi$
D) $81 \pi$