Refer to the exhibit.
What do all the calls shown in the sequence diagram have in common?
A. All the calls are optional.
B. All the calls are asynchronous.
C. All the calls are synchronous.
D. All the calls depend on the catalog.
Refer to the exhibit.
What do all the calls shown in the sequence diagram have in common?
A. All the calls are optional.
B. All the calls are asynchronous.
C. All the calls are synchronous.
D. All the calls depend on the catalog.