A company that manufactures storage bins for grains made a drawing of a silo. The silo has a conical base, as shown below: The figure shows a silo shaped as a closed cylinder with a conical end. The diameter of the silo is 4 ft, the length of the cylindrical part is 8.5 ft, and the entire length of the silo is 13 ft.

Which of the following could be used to calculate the total volume of grains that can be stored in the silo?
π(8.5ft)2(2ft) + one over threeπ(2ft)2(13ft − 8.5ft)
π(2ft)2(8.5ft) + one over threeπ(2ft)2(13ft − 8.5ft)
π(8.5ft)2(2ft) + one over threeπ(13ft − 8.5ft)2(2ft)
π(2ft)2(8.5ft) + one over threeπ(13ft − 8.5ft)2(2ft)