What is the other name for a system boundary?

• A. The subject
• B. The trigger
• C. The main success scenario
• D. The postconditions

Answer: (A)

Think of the system boundary as the line that separates what belongs to the system from everything outside it. In many modeling contexts, this boundary is described using the term the subject—the system itself being the subject of the analysis. The boundary defines the scope: inside it are the functions the system performs, while outside are the actors and other systems that interact with it.

The other concepts refer to different ideas in use-case modeling. A trigger is what starts a use case, the main success scenario is the normal sequence of steps that achieves the goal, and postconditions describe the state after the use case completes. None of those describe the boundary itself, whereas the subject labeling is a common way to denote the system under consideration.