Determine the Diameter of a Hole That Is Drilled Vertically $z = 28 e ^ { - \left( x ^ { 2 } + y ^ { 2 } \right) / 4 } , z = 0$

Multiple Choice

Determine the diameter of a hole that is drilled vertically through the center of the solid bounded by the graphs of the equations $z = 28 e ^ { - \left( x ^ { 2 } + y ^ { 2 } \right) / 4 } , z = 0$ , and $x ^ { 2 } + y ^ { 2 } = 9$ if one-tenth of the volume of the solid is removed. Round your answer to four decimal places.

A) $1.2245$
B) $31.4490$
C) $7.2245$
D) $5.4490$
E) $15.2245$