Which fragment represents two or more alternative sets of event occurrences during an execution?

Which fragment represents two or more alternative sets of event occurrences during an execution?

• A. opt combined fragment
• B. alt combined fragment
• C. loop combined fragment
• D. parallel combined fragment

Answer: (B)

In UML activity diagrams, an alt combined fragment models a choice between multiple alternative sequences. It allows two or more paths to be defined, but exactly one path is taken in a single execution based on the guard conditions. This matches the idea of two or more alternative sets of event occurrences during execution, since you select which set of events actually happens. The other fragment types behave differently: an opt fragment makes a path optional (it may or may not occur), a loop fragment repeats a sequence, and a parallel fragment runs multiple sequences concurrently.

In UML activity diagrams, an alt combined fragment models a choice between multiple alternative sequences. It allows two or more paths to be defined, but exactly one path is taken in a single execution based on the guard conditions. This matches the idea of two or more alternative sets of event occurrences during execution, since you select which set of events actually happens. The other fragment types behave differently: an opt fragment makes a path optional (it may or may not occur), a loop fragment repeats a sequence, and a parallel fragment runs multiple sequences concurrently.