What marks the behavior termination occurrence in a sequence diagram?

What marks the behavior termination occurrence in a sequence diagram?

• A. At the point where a lifeline sends a reply message
• B. At the point where a lifeline receives a synchronous or asynchronous message
• C. When the lifeline is created
• D. At the end of the interaction

Answer: (A)

In a sequence diagram, the moment a behavior that started with a call ends is shown by the lifeline sending a reply message back to the caller. That reply signals the operation has finished and control returns to the caller, marking the termination of that specific behavior occurrence. Creating a lifeline starts an instance, not ends it; receiving a message is just an event that can trigger actions, not the end of the behavior; and the end of the entire interaction is a broader conclusion, not the precise termination point of a single behavior.

In a sequence diagram, the moment a behavior that started with a call ends is shown by the lifeline sending a reply message back to the caller. That reply signals the operation has finished and control returns to the caller, marking the termination of that specific behavior occurrence. Creating a lifeline starts an instance, not ends it; receiving a message is just an event that can trigger actions, not the end of the behavior; and the end of the entire interaction is a broader conclusion, not the precise termination point of a single behavior.