How can nationalism be considered a cause of World War I?

Nationalism encouraged ethnic groups to seek independence or dominance, heightening tensions within multiethnic empires such as Austria-Hungary and the Ottoman Empire. These conflicts destabilized Europe and helped create the conditions for war, so B, “Nationalism created ethnic tensions, resulting in civil war,” is the best choice. Economic competition is more directly associated with imperialism and rivalries among powers, making A less accurate.

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