Which condition best explains why World War I started? O a system of military alliances in Europe and nationalism on the Balkan Peninsula
O the clash of capitalism and communism in European nations
O imperialism in South America and Asia and the rapid buildup of armies and navies
O the spread of communism from Russia into western Asia

A system of military alliances in Europe and Nationalism in the Balkan peninsula

My best answer choice

Explanation:

One serbian man kicked the hornet's nest by assassinating the heir to the Austria-Hungarian throne Franz Ferdinand. This ultimately caused the First world war alongside socio-economic issues brewing in the regions for years.