Nationalism:

A. was a potential threat to the existing political order.
B. had major support only in western, Atlantic coast Europe until the late 1860s.
C. was firmly opposed by Bismarck and Cavour.
D. won speedy acceptance across Europe because every government was helped by it.

A

just read the name

A. was a potential threat to the existing political order.

To determine the correct answer to the question regarding nationalism, we can evaluate each option:

A. was a potential threat to the existing political order.
To determine if this option is correct, we should examine the historical context. Nationalism often emerged as a response to oppressive political regimes or the desire for self-determination. It challenged existing political orders by promoting the idea of a unified nation under a common identity. Thus, option A is a correct statement.

B. had major support only in western, Atlantic coast Europe until the late 1860s.
To determine if this option is correct, we need to consider the historical spread of nationalism. While nationalism did have significant support in western and Atlantic coast Europe, it extended beyond these regions. Nationalist movements were present in various parts of Europe, including Eastern Europe and areas under colonial rule. As such, option B is incorrect.

C. was firmly opposed by Bismarck and Cavour.
To evaluate if this option is correct, we should examine the role of key historical figures in relation to nationalism. Bismarck and Cavour were prominent figures who supported nationalist movements in their respective regions. Bismarck played a significant role in the unification of Germany through nationalist ideologies, while Cavour was instrumental in the unification of Italy. Therefore, option C is incorrect.

D. won speedy acceptance across Europe because every government was helped by it.
To assess if this option is correct, we need to understand the response of different European governments to nationalism. While some governments indeed embraced nationalism to consolidate their power, others resisted it as a threat to their authority. The acceptance and promotion of nationalism varied across different nations. Therefore, option D is incorrect.

In summary, the correct answer to the question is:

A. was a potential threat to the existing political order.