Final answer:
The formula V = πr² is for the area of a circle and cannot be directly converted into the volume of a sphere; however, the correct formula for the volume of a sphere, not provided in the options, is V = 4/3 πr³.
Step-by-step explanation:
The formula for the volume of a sphere is represented as V = 4/3 πr³, where π (pi) is approximately equal to 3.14159, and 'r' stands for the radius of the sphere. The given formula V = πr² is actually the formula for the area of a circle, and is not directly related to the volume of a sphere.
However, if the intention is to depict the volume of a solid related to the area of a circle, which only has two dimensions, one might consider the volume of a cylinder or the cone. Neither of these is mentioned in the given options. Thus, based on the options provided and the fact that the area of a circle is not sufficient to determine the three-dimensional volume of a sphere, none of the listed options (a, b, c, d) are correctly expressed in terms of the area of a circle (A = πr²).