Answer:
Correct answer is b)The Industrial Revolution .
Explanation:
Although all of the mentioned events had a lot of impact to the spreading of Imperialism the correct answer is Industrial Revolution.
The answer is simply because European countries needed more raw materials and resources and the easiest way to obtain them was by spreading their power and establishing new colonies.
Therefore industrial revolution and imperialism are closely connected.
French Revolution inspired other revolutions not only imperialism.
Unification of Italy and Germany came in the second half of 19th Century when imperialism was already spreading.
Congress of Vienna tried to stabilize situation in Europe.
