Which of the following was a cause of World War II?

Nazi aggression in Europe was a significant cause of World War II, as it directly influenced the outbreak of the conflict. After Adolf Hitler came to power in Germany, he pursued an expansionist policy that defied the Treaty of Versailles, which had been created to ensure peace after World War I. Hitler's actions included the remilitarization of the Rhineland, the annexation of Austria, and the subsequent invasion of Czechoslovakia, all of which demonstrated his intent to restore Germany's power and territory.

These aggressive actions alarmed other countries and led to a chain reaction among European nations. The failure of appeasement strategies, where countries like Britain and France tried to avoid conflict by allowing limited German expansion, only emboldened Hitler and led to further aggression. The culmination of these actions was the invasion of Poland in September 1939, which prompted Britain and France to declare war on Germany, marking the official start of World War II.

Other options, such as democratic peace movements, the rise of socialism, and global trade agreements, do not directly correlate with the immediate causes of the war in the same way. While each of these factors had a role in the broader context of interwar politics and economics, it was the direct