Question

by july of 1950, even with the help of us troops, north korean forces had pushed south korean forces as far south as
seoul
inchon
pyongyang
pusan perimeter

Explanation:

In the early stages of the Korean War (1950), North Korean forces, even with US troops aiding South Korea initially, pushed South Korean forces down to the Pusan Perimeter (a defensive line around the port city of Pusan in the far south of the Korean Peninsula). Seoul was captured earlier, Inchon was the site of a later UN landing, and Pyongyang is in North Korea.

Answer:

D. Pusan Perimeter