The correct answer is this.
Popular sovereignty means that government is by the people.
The political concept of popular sovereignty means that it is the people that grant the power to the government to rule over them. The form of government can exist because it is the people, the citizens, who accept to be governed. That is why they accept participating in elections to select their representatives.
In the case of the United States, the framers of the US Constitution were influenced by Renaissance ideas from great philosophers such as Voltaire, John Locke, Baron of Montesquiou, and Jean-Jaques Rosseau.