Answer: Set the lifeline of each object
Explanation:
The sequence diagram is the efficient way that use in the system requirement document for the system design.
The sequence diagram is useful in many system that shows the interaction of the logic between the each object in the system.
The first step for building the sequence diagram is that set the lifeline of the each object in the system and it allow the main specification in the run time scenarios in the graphical manner. Therefore, it enhance the performance of the system.