Look at the map and answer the following question.

Based on the map of the Korean War, which of the following statements is correct?
a.
The city of Pusan was under North Korean and South Korean control at different points in the war.
b.
The city of Pusan was under North Korean control for only a brief period in 1951.
c.
North Korean lost control of the city of Pusan very early on in the war and never regained it.
d.
The city of Pusan was never under North Korean control at any point in the war.