A

By striking in an area far away from where the fighting had been concentrated.

Explanation:

The United States Marines took the port of Inchon, South Korea, on September 15, 1950, during the Korean War. Inchon city (see the map below) was located 25 miles from Seoul that had fallen to North Korean troops in June and 100 miles from the 38th parallel. The landing was considered risky but the General MacArthur insisted that the operation should be carried out.

Inchon invasion allowed the United States to block North Korean supply and recapture Seoul. Inchon landing was significant for the Korean War, as it led to important changes in its course.

Map of the Korean peninsula during the Korean War .
Map of the Korean peninsula during the Korean War (Source: www.nam.ac.uk)