Find the Volume of the Solid Generated by Revolving the Region

Multiple Choice

Find the volume of the solid generated by revolving the region bounded by the given lines and curves about the x-axis.
- $$y = \sqrt { 81 - x ^ { 2 } } , y = 0 , x = 0 , x = 9$$

A) $486 \pi$
B) $972 \pi$
C) $18 \pi$
D) $324 \pi$