Answer: The answer is (D) A cylinder is exactly 3 times bigger than a cone with the same height and radius. Therefore, the formula for the volume of a cone is 1/3 of the volume of a cylinder with the same height and radius.
Step-by-step explanation: We know that a Cone is a three-dimensional geometric figure with a circular base as shown in the attached figure (a). In fact, a Cone is a pyramid with a circular cross-section.
The volume of a Cone and a Cylinder are related to each other. The volume of a cylinder is

and the volume of a cone is

Therefore, if the radius of the base and height of a cone and a cylinder are same, the the volume of the cone is one-third of the volume of cylinder. So, we can join 3 cones together to form a single cylinder having radius and height equal to the radius of base and height respectively of the cone. See the attached figure (b).
Thus, the correct option is (D).