Answer:
The correct answer is D, elect leaders to represent them in government.
Explanation:
The idea of Republic was born in human history in opposition to the monarchical form of government, in which the leader is chosen according to who are his/her parents. Thus, the Republic is primarily the political regime where the leader is chosen by the people to represent them in the government. The keyword here is elected political representation.
How the people choose the leader, whether is it directly or indirectly and if the people get to participate directly in most of the government decisions, is indicative of how democratic is that regime.
The concept of Republic changes over time according to different historical contexts.