Final answer:
The volume of a sphere with a radius of 18 units is approximately 58327 units³.
Step-by-step explanation:
The volume of a sphere can be calculated using the formula V = πr³, where r is the radius of the sphere.
Substituting the given radius of 18 units into the formula, we have V = π(18)³ = 58320π units³.
Therefore, the volume of a sphere with a radius of 18 units is approximately 58327 units³, option C.