Final answer:
The causes of World War I were a combination of Militarism, Alliances, Imperialism, and Nationalism, with the immediate spark being the assassination of Archduke Franz Ferdinand.
Step-by-step explanation:
The causes of World War I are often summarized by the acronym MAIN, which stands for Militarism, Alliances, Imperialism, and Nationalism. These long-term factors set the stage for a large-scale conflict, creating an environment ripe for war. Militarism involved the arms race as nations built up their military capabilities. Alliances, such as the Triple Entente and the Triple Alliance, created networks of mutual defense obligations. Imperialism led to competition for colonies and global influence, while nationalism drove countries to assert their dominance and right to self-determination.
However, it was the assassination of Archduke Franz Ferdinand of Austro-Hungary by a Serbian nationalist that provided the immediate spark that ignited the war. With tensions high and alliances in place, the assassination led to a domino effect of ultimatums and declarations of war. Therefore, the correct combination of causes that led to WWI, as per the question's options, would include Imperialism, Nationalism, Militarism, Alliance System, and the Assassination of Archduke Franz Ferdinand.