Below are the choices that can be found from other sources:
A) 36 pi
B) 6 pi
C) 27 pi
D) 216 pi
E) 48 pi
A sphere's volume is (4/3)*pi*r^3.
The diameter of the balloon is 6 inches. The diameter is twice the radius. The radius is 3 inches.
(4/3)*pi*3^3 = 36 * pi
But the balloon is only 3/4 full. So
36 * (3/4) * pi = 27 * pi.
The balloon has 27 pi cubic inches of water.