Answer:
The correct answer is: the Cold War .
Step-by-step explanation:
The Cold War refers to the geopolitical, ideological and economic tension between the Soviet Union and the U.S., that started shortly after the Second World War (in 1947) and lasted until the dissolution of the Soviet Union (in 1991).
After World War Two, the Soviets established left-wing governments in the countries of eastern Europe. The U.S. feared the permanent Soviet domination of Eastern Europe, along with the influence of the Communist party, as the U.S. was under the democratic regime with protected human rights (freedom of speech, religion and the press freedom).
Americans were also concerned about Stalin's dictatorship that demanded equality for all classes of people and also had a strong impact on the Soviet economy. This was a communist economy, that is the system where the government was controlling and owning everything, while in the U.S. was arising the capitalist economy, based on free trade and private property.
Under these circumstances, the War was practically inevitable.