Which has been a direct effect of nationalism in Europe?

"The split of the Austro-Hungarian Empire" has been a direct effect of nationalism in Europe.

Explanation:

The Austro-Hungarian Empire was separated because of the few ethnicities residing in the Empire with many beliefs and cultures. Nationalists made various cultural groups in order to join their efforts and call for autonomy to make country states. (Nationalism is characterized as distinguishing proof with one's very own country and support for it's regard, especially to the avoidance or weakness to the interests of different countries.)

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b. parliament was weaker than the monarchy.

the answer would be c