What is considered one cause of world war i?

a. germany broke a promise to the united nations by attacking
poland.

b. several european countries experienced the rise of fascist
dictators.

c. king leopold of belgium was assassinated by serbian activists.

d. european countries built up enormous armies to protect their
colonies.

The right answer is D.

Explanation:

Britain, France and Belgium and other European powers had acquired vast empires in Africa, Asia and Oceania. They had to protect their possessions and mobilized enormous resources. They also established a network of military alliances in Europe, and this is also seen as a major factor of the start of armed actions in 1914.

gain an alliance with britain

Explanation: