The principle of popular sovereignty primarily refers to the idea that the authority of the government is created and sustained by the consent of its people, typically expressed through their elected representatives. Therefore, among the options you provided, the most closely aligned with the concept of popular sovereignty is "the people have the right to alter their government."
This embodies the fundamental aspect of popular sovereignty, which is that the power resides with the people, and they have the ultimate authority to change their government as they see fit. The other options you mentioned relate to different aspects of the government's structure or functions but do not directly represent the core idea of popular sovereignty.