The volume of the silo is approximately equal to 1047.2 cubic feet. (Correct choice: D)
How to determine the volume of a silo
In this problem we must determine the volume of a silo, which is the sum of the volumes of two cones and a right cylinder, whose volume formulae are, respectively:
Cone

Where:
- r - Radius, in feet.
- h - Height, in feet.
- V - Volume, in cubic feet.
Cylinder

Now we proceed to compute the volume of the silo by substituting terms and adding each component:

V = 1047.198 ft³
The silo has a volume of approximately 1047.198 ft³.