Which of the following represents a derived value property?

A derived value property is a value that is computed based on other values or properties rather than being explicitly defined. The representation of derived values often utilizes a notation that indicates the value is derived from a calculation or rule.

In this context, "/period" signifies a derived value property because it typically implies a calculation or a measurement that derives its value based on conditions or operations applied to other elements of the model. The use of a leading slash often indicates that the value is not directly assigned but is instead inferred from other attributes within the model.

Conversely, the other options—activity, constraint, and state machine—represent different elements of modeling. Activities are tasks or actions performed, constraints represent limitations or conditions that restrict behavior, and state machines represent a model of states and transitions. None of these options denote a derived value in the same manner as "/period," which specifically indicates a derived property associated with computation or dependency on other values.