Which factor contributed most to the beginning of World War I?

Dissatisfaction of Central Powers with the colonial division.

Explanation:

The struggle for colonies between the two enemy blocs, the Central Powers and the Entente was the cause of the war. Central Powers sought to reach the colonies. This conflict, the largest so far, has been called the First World War. When it comes to the Balkans, Germany and Austria-Hungary seek to use it to penetrate the Near and Middle East.