In the context of UML 2.0 and the specifications around Decision Nodes, option C is the correct choice.
According to the UML 2.5 specification, when a Decision Node has an incoming control flow and a decisionInput, thedecisionInputmust have a single input parameter (in Parameter). This ensures that the decision node can evaluate the decision input using the value passed through the incoming control flow. This mechanism is crucial for decision-making processes within activity diagrams where decisions are made based on dynamic data provided at runtime.
References:
* UML 2.5 Specification: The specification details the properties and behaviors of Decision Nodes within activity diagrams, particularly emphasizing how decision inputs and their parameters are handled.