Answer:
The good choice is:
German unification and Kaiser Wilhelm's diplomacy.
Explanation:
The unification of Germany in 1871 put an economic and political giant in the middle of Europe. As German economic might grew and the country became an industrial power, it also wanted to play a larger role in world affaris and launched itself to the race for colonies. Russia, France and Britain formed an alliance to check German power. Germany allied itself with Austria-Hungary. This rigid and threatening system of alliances was one factor that favored the outbreak of World War One in 1914.
