I think one of the advantages that North Korea had was the
support of the Soviet Union and China. Both countries are well equipped with
tanks and artillery while the South Korean army was only arm with smaller
weapon. The US tried not to get involve first, which lead to Stalin releasing
nuclear bombs to threaten South Korea and the US
The answer is D, having to fight a two-front war.
The Schlieffen plan was the German strategy to quickly take out France so that they could focus all their troops on Russia.
The Answer for this is France. :)