What factors contributed to the United States becoming a world leader? ОА.
the United States winning the war and having a strong economy
OB.
the Allies winning the war and US having a skilled labor force
OC.
the United States winning the war and German scientists sharing their knowledge
the United States suffering no war damage and having a strong economy
D.

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.

a system of cooperative federalism emerged, as the powers of the federal government expanded.