What is a defining characteristic of setter properties?

Setter properties are designed to facilitate the modification of an associated object's state by accepting a single input value. When you invoke a setter property, you typically provide a new value, and the property logic will handle updating the object's internal state accordingly. This encapsulation enables controlled modifications to the object's attributes, maintaining the integrity of the class design.

The other options present characteristics that do not align with the purpose of setter properties. For instance, returning computed values pertains more to getter properties, which retrieve and often compute values for the caller. The notion of modifying static variables does not fit with the intended use of setters, as setters are generally associated with instance variables, and their function is not limited to static context. Additionally, creating new instances of objects is more characteristic of constructors rather than setters, which focus on altering the existing value of an object's property rather than instantiating new objects.