Which of the following was NOT a cause of World War I?

The choice indicating colonial expansion as a cause of World War I is not considered one of the primary factors contributing to the war. Instead, nationalism, imperialism, and militarism are widely recognized as significant causes.

Nationalism promoted intense national pride and competition among nations, leading to tensions and conflicts. Countries sought to assert their dominance and protect their interests, which often culminated in a desire for war.

Imperialism involved the competition for colonies and global dominance. Many countries sought to expand their empires, which heightened rivalries and contributed to the overarching conflict.

Militarism refers to the arms race and the emphasis on military preparedness and strategy. Nations built up their military forces in anticipation of conflict, further escalating tensions.

While colonial expansion can be seen as part of the larger imperialistic ambitions that fueled the war, it is not singled out as a direct cause like nationalism, imperialism, or militarism are, which are more directly linked to the events leading up to World War I. Therefore, emphasizing colonial expansion as the non-causal factor among these options is appropriate.