What prompts a Change Event to occur?

A Change Event is specifically triggered when a Boolean expression transitions from false to true. This condition signifies a meaningful change in the system's state or in the context of the model, indicating that a certain condition has been met.

Understanding this mechanism is crucial in modeling because it allows for the identification of when a significant event occurs and can drive subsequent actions or behaviors in the system. For instance, in many modeling scenarios, a Change Event represents a threshold or a trigger point that, once crossed, can result in further processing or activity.

The other answer options may describe conditions that are relevant in different contexts or types of events, but they do not accurately capture the essence of what defines a Change Event in the context of modeling. The focus on the transition from false to true is what makes option C the precise and correct choice for prompting a Change Event.