Question

By the beginning of October of 1950, UN forces had pushed the North Koreans back to

Answer 1

By the beginning of October of 1950, UN forces had pushed the North Koreans back to the Yalu River. Option three is correct.

By September 1950, UN forces led by the American General MacArthur landed in Inchon and immediately pushed the North Koreans back over the 38th parallel. Later on, by October 1950 they had  rolled back the communists to the Yalu River on the border with China.

Answer 2

By the beginning of October of 1950, UN forces had pushed the North Koreans back to the 38th parallel. It is the line that divided the Korean Peninsula into two countries, North Korea and South Korea.  

Further Explanation

At the end of the Second World War, Korea was liberated from Japan. The United States and the Soviet Union agreed to divide the country into two, North Korea, under the Soviet Union and South Korea, under the United States. The border set on the 38th parallel.  

On 1950 North Korea invaded South Korea. They want to unify Korea under North Korea's control.  

Then on July, The USA sent troops to South Korea. UN forces, led by the United States pushed the North Koreans back to the 38th parallel on the beginning of October 1950.  

On July 1953, the Korean Armistice Agreement was signed in Panmunjon and left the Peninsula divided into two. The border between the two countries then set in the Korean Demilitarized Zone (DMZ).

Technically, both countries still in the war at the moment. But in 2018, the North Korean leader, Kim Jong-un and the South Korean leader, Moon Jae-in agreed to work together to formally end the Korean War.

Learn more

Korean War brainly.com/question/1351858

Korean War brainly.com/question/1083893

Keywords: Korean War, Korean History, South Korea, North Korea, 38th parallel