Final answer:
A nation-state features a government with sovereignty within its territory, control of military power to support its sovereignty, and a population often from homogeneous backgrounds promoting a common national identity. The correct answer is option A.
Step-by-step explanation:
A characteristic of a nation-state is that it has a government apparatus that is sovereign within its territory. The government has the authority to exercise centralized rule, create and enforce laws, collect taxes, build infrastructure, and organize the economy. Additionally, a nation-state maintains a monopoly on the use of force through the military and police to back its sovereignty.
A nation-state is distinguished by having a specific territory, a permanent population, and recognized boundaries. Sovereignty is a critical element, meaning the state has ultimate authority within its territory and does not need to seek the direct authority of any other nation. Most nation-states are built from communities with similar backgrounds, emphasizing a common national identity, often manifesting through symbols such as flags, anthems, and national holidays, and institutions that promote unity and peoplehood.