Which country became involved in the Korean War to stop the spread of communism?

The correct answer is c. the United States.

During the Korean War, which lasted from 1950 to 1953, the United States entered the conflict to support South Korea and prevent the spread of communism in the region. The involvement was part of a broader strategy known as the “Domino Theory,” which suggested that if one country fell to communism, neighboring countries would also be at risk.