The correct answer to this question is the following.
1.- the Enlightenment.
2.- Matternich's initiatives to curb nationalism.
3.- sweep of revolutions across Europe.
4- formation of the kingdom of Italy.
The Enlightenment or Age of Reason was the period in the 18th century when thinkers, philosophers, and scientists changed the world with their ideas and advancements. The ideas of Locke, Hobbes, Montesquieu, and Jean-Jaques Russeau were very influential.
The Matternich's initiatives to curb nationalism started in 1815 and ended in 1845. It was a 33 years period in which the industrialization of Europe and specifically in Austria had some advantages and some disadvantages that created some issues on people.
In 1848, a series of Revolutions in Europe against their respective monarchies started in Italy, France, Germany, and other regions of the continent. And finally, in 1861, the House of Savoy started to unified the territories of southern Italy, to create the kingdom of Italy.