Final answer:
Victor Emmanuel's actions towards the Italian parliament demonstrate the role of nationalism in the lead-up to the Great War. Nationalism fueled the desire for unified national states, contributing to tensions and rivalries which were among the factors that triggered World War I. The correct option is A.
Step-by-step explanation:
Victor Emmanuel's space in the Italian parliament best illustrates the cause of the Great War related to nationalism. Nationalism was a powerful ideology in the nineteenth century that fostered a desire among various ethnic and cultural groups in Europe to form their independent nations.
The movement for Italian unification, led by figures like Giuseppe Mazzini and capitalized upon by leaders like Victor Emmanuel II and Count Cavour, was driven by the call for sovereignty and the unification of the Italian states into a single nation. This push for national self-determination was in direct contrast with the multi-ethnic empires like Austria-Hungary and the Ottoman Empire, where nationalist sentiments threatened to pull these empires apart.
Nationalism was a significant factor that contributed to the tensions leading up to the Great War. Fueled by a sense of patriotism and the desire for national prestige, the rivalries between the great powers of Europe increased, and eventually, this contributed to the onset of World War I.