Answer:
D) European superiority in military organization and discipline
Step-by-step explanation:
Europa was facing Nationalism in the 19th century, which created a sense of unity, identity, and organization, giving to them military superiority in comparison to Asia, Africa, and Oceania. Another important point is the isolation of these locations, or the social and military fragility of some (Asia and Africa, for example). Then, European superiority was strongly based on Nationalism and Unity, different from the others which were almost primitive such as Oceania populations, or was always struggling with wars and political coup d'etat.