I would choose "representative democracy" as the best answer- this is the most typical example for what you described
Some other forms would also qualify in some cases, for example The Vatican city (Theocracy and absolute ?monarchy?) also has an elective leader, albeit for life.
but "representative democracy" is best.
Examples of representative democracy: US, Germany, UK.
It is A, for someone reason its saying 20 words so dont mind this part