What is a destruction occurrence?

• A. Represents the termination of a lifeline and the destruction of the instance within a system that the lifeline represents
• B. Represents a create event
• C. Represents a reply
• D. Represents an asynchronous message

Answer: (A)

A destruction occurrence marks the end of an object's life in a sequence diagram. It’s shown as an X on the object’s lifeline, signaling that at that moment the instance is destroyed and its lifeline ends. After this point, no further messages can be sent to that object. This is different from a create event (which shows an object coming into existence), a reply (which is a response to a request), or an asynchronous message (which is simply a non-blocking communication between lifelines).