What Is the Central Idea of a Democracy

What is the central idea of a democracy?

A) Ordinary people want to rule themselves and are capable of doing so.
B) Ordinary people want representatives to govern them.
C) Governing should be carried out by a select few or by a single, enlightened leader.
D) Every person in the country should be allowed to vote.
E) Security, along with religious laws and values, is the most important function of government.