The third alternative is correct (C).
World War I was a large-scale conflict in the second decade of the twentieth century that involved major powers from Europe and other continents, as well as countries around the globe that had some connection with these powers.
The political, economic and military conjuncture that led to the conflict formed throughout the end of the 19th century and covered the whole of the 20th century creating the conditions for the war to burst in 1914. Thus, several facts can be pointed out as causes of World War I , among which, Imperialism.
Imperialism had a character of dominance on the part of the powers in relation to the underdeveloped countries rich in natural resources. This led the European powers to seek an effective increase of their influence in the external scenario, generating conflicts that fed the rivalry and the nationalism in those countries, being a fuel for the first war.