what is meant by the basic principle popular soverignthy?

a the government is set up as a constitutional republic
b the people have the right to alter their government
c congress has the right to regulate trade
d the president has the right to veto any bill that congress has passed

The basic principle of popular sovereignty refers to the concept that the people have the ultimate authority and power in a democratic government. It means that the government is established and operates with the consent of the people. Option b - "the people have the right to alter their government" - best reflects the concept of popular sovereignty.