Answer:
D. nationalism and imperialism
Step-by-step explanation:
The World War one was a result of two things, the strong nationalism and the imperialist ambitions. As the nationalism was growing stronger and stronger, the countries were trying to get more and more territory, usually having the excuse that it is a territory that historically was inhabited or still is by that particular group of people. This of course led to lot of tensions as that meant annexation, occupation, and invasion. Another important factor was the imperialist ambitions, as all the powerful countries in Europe wanted to have a piece of the colonies and their resources, at if they did to have more. These two things caused such big conflict of interest that a World War broke up and unfortunately millions of people lost their lives, families, homes.