When may the name of the location or the call sign suffix in the call sign of an aeronautical station be omitted ?

Question

Question ATPL - Airline Transport Pilot license - VFR Communications

QuizVDS · Accepted Answer

When satisfactory communication has been established and provided it will not be confusing to do so

QuizVDS · Answer

Only after the aeronautical station has used the abbreviated call sign

QuizVDS · Answer

Never

QuizVDS · Answer

In dense traffic during rush hours

Id 69 - ATPL - When may the name of the location or the call sign suffix in the call sign of an aeronautical station be omitted ?