(A) ** European Nations were eager to gain the colonial territories owned by their rivals.
(B) European nations were eager to show their military might by fighting with one another.
(C) European nations were eager to take sides with other nations.
(D) European nations all felt that their nation was superior to others.
EXPLANATIONS BELOW
Concept note-1: -European Expansionism The expansion of European nations as empires (also known as imperialism) can be seen as a key cause of World War I, because as countries like Britain and France expanded their empires, it resulted in increased tensions among European countries.
Concept note-2: -Colonial rivalry was a cause of the First World War. First of all, colonial rivalry led to strained relations among the European powers. In Africa, all the European powers except Austria and Russia had colonies there. Thus there were many clashes among France, Britain, Germany and Italy.