The correct answer to this open question is the following.
Although there are no options attached we can say the following,
The South Korean city was Inchon, a port on the west coast that General Douglass McArthur boldly decided to invade in order to recapture Seoul, the capital city of South Korea that had been fallen to the North Korean troops in June 1950.
The invasion of Inchon happened on September 15, 1950m as part of the Korean War during the Cold War years. Inchon is located approximately 25 miles from Seul.
The Soviet Union was trying to spread Communism in different parts of the world, Korea included. Indeed, the Soviet Union had been supported North Korea.
That is why the United States and the United Nations had to intervene to help South Korea. The US federal government feared the "Domino Effect," in which, if one nation converted to Communism, it was probably that other nations would follow.