What led to the rise of nationalism throughout Europe?

Question

A. National upheavals that began during the revolutions of 1858 caused nationalism to spread through Europe.
B. Nation-states rebelled against the international organization created by the Congress of Vienna.
C. In the wake of the Napoleonic Wars, disjointed territories banded together for protection as a common goal.
D. The collapse of the Weimar Republic in Germany led to the reunification of the country, inspiring other countries to nationalism
the answer is A?

Answer 1

A is wrong