Nationalism is to pride in one's national identity as a is to a group of people who share a common identity, a sense of unity, and a desire for self-government.
a. state
b. nation
c. region
d. country

The answer is Nation is to a group of people who share a common identity, a sense of unity, and a desire for self-government. A country would be bordered territories with governments that control internal and external affairs. A state is an organized political community under a single system of government.
A region is an area of Earth that distinguishes itself from other areas by the human and physical characteristics within it.