Topic: Substitution, Expression, & Definition,

Best Answer Explained in Below-:

The term "Cosmopolitan" refers to an individual who identifies with the global community rather than a specific nation or locality. This perspective embraces diversity and inclusivity, viewing the world as one's country. Cosmopolitans often emphasize interconnectedness among people, transcending national boundaries and prioritizing humanity over territorial affiliations.

In contrast, the other options do not align with this universal outlook. A "Nationalist" exclusively prioritizes the interests and culture of a specific nation, while a "Patriot" displays strong loyalty and love for their country, often in a nationalistic sense. "Metropolitan" typically refers to someone who lives in or is associated with a large city, without necessarily implying a broader global perspective.

Therefore, the correct answer to the statement "A person who regards the whole as his country" is indeed **A) Cosmopolitan**, as it encapsulates the ethos of global citizenship and universal belonging that transcends individual nations.