Answer: The answer is not a, c, or d. The correct answer is:
The powerful impact of nationalism in 19th-century Europe was the unification of Germany and Italy.
Step-by-step explanation:
The powerful impact of nationalism in 19th-century Europe was the unification of Germany and Italy. Nationalism led to the development of a sense of shared identity and pride among people within specific geographic regions, and this led to the desire for political unification. In the case of Germany, nationalism helped to bring together various independent states and territories into a single nation-state under the leadership of Prussia. Similarly, nationalism was a significant factor in the unification of Italy. The sense of shared identity and pride fueled the efforts of Italian nationalists to bring together various regions and states into a single country. Nationalism, therefore, played a critical role in the shaping of European history in the 19th century.