This period was a time of great political unrest, which divided Europe into eastern and western sections.

a. Cold War
b. Imperialist
c. Middle Ages
d. Yalta Conference

The Cold War

Midddle Ages

The Cold War...

cold war

To identify which option is the correct answer, we need to understand the context of the question. The given information states that this period was characterized by political unrest, which divided Europe into eastern and western sections.

- Imperialism refers to the policy of extending a country's power and influence through colonization, but it does not inherently relate to the division of Europe into eastern and western sections.
- The Middle Ages refers to a historical period between the 5th and 15th centuries, which is unrelated to the political unrest and division mentioned in the question.
- The Yalta Conference occurred during World War II and was a meeting between the leaders of the Allied powers (the Soviet Union, the United States, and the United Kingdom) to discuss post-war reorganization. While it shaped the post-war order, it does not specifically refer to the division of Europe into eastern and western sections.

Thus, the best answer is option a: Cold War. The Cold War, which lasted from the late 1940s to the early 1990s, was a period of significant political tension and division between the Eastern Bloc (led by the Soviet Union) and the Western Bloc (led by the United States). This division resulted in the physical separation of Europe into eastern and western regions, with the Iron Curtain acting as a symbolic representation of this division.