Answer:
C. Communism was contained to its prewar borders.
Step-by-step explanation:
This is the element that could be considered a success when we look at the way the Korean War developed. The Korean War was not a success when it came to the return of the prisoners of war. Moreover, North Korea was not deminlitarized, nor did it abandoned its alliance with the Soviet Union. However, the Korean War could be considered a success because communism did not expand all over the peninsula, but was instead contained to its prewar borders.