The Constitution reflects the principle of popular sovereignty primarily by allowing the people to choose their representatives. Popular sovereignty is the idea that the authority of the government is created and sustained by the consent of its people, typically through their elected representatives. The Constitution establishes a representative democracy where officials are chosen through elections, ensuring that the government reflects the will of the people.
While the other options you mentioned (limiting government power, placing protections on civil rights, and implementing safeguards against abuse of power) are important features of the Constitution, they serve to support and protect the principles of popular sovereignty rather than embody them directly. Ultimately, the choice of representatives is the most direct expression of the sovereignty of the people.