Akey factor of the empires the united states and european countries built in the late 1800s was:

The correct answer is D) nationalism.

A key factor of the empires the United States and Great Britain built in the late 1800s was nationalism.

The ideology that considers that people had to be devoted to his nation is called Nationalism. This term indicates that individuals profess extreme love and respect for their country and that the benefit of the nation is above all other interests.

For the United States, the Manifested Destiny, a great Nationalistic concept, drove the imperialistic and expansionistic deeds to gain more territory such as the annexation of California, Arizona or New Mexico. The case of the British is similar, nationalistic ideas made them sent explorers to colonize new lands to increase the territories and richness of the English crown.

The other options of the question were a) totalitarianism, b) patriotism, and c) chauvinism.  

i told you before its c

it increased the power of the king of england.