Popular sovereignty refers to the concept of governance where the ultimate power lies with the people. Option 1, "Sovereignty of peoples representative," is not accurate because popular sovereignty does not indicate the sovereignty of representatives chosen by the people but rather the sovereignty of the people themselves. Option 2, "Sovereignty of the legal head," and Option 3, "Sovereignty of the head of state," are also incorrect as they refer to the sovereignty of specific individuals or positions within the government, rather than the entire population. The correct option is 4, "Sovereignty of the people," which accurately represents the idea that the people have the ultimate authority and control in making decisions and determining the course of their government.