What were the results of the Chinese army crossing the Yalu River?
A) Kim il Sung led the Chinese forces to capture the city of Seoul in the Spring Offensive.
B) American forces were encircled by the Chinese army at Chosin and needed air support.
C) American forces turned the tide to push the Chinese forces back to the Yalu River.
D) Joseph Stalin coordinated efforts between the Soviet and Chinese forces during the war.