C Most Europeans believed the war would end quickly, but it bogged down in trench warfare.
Explanation:
Trench warfare or war of position is a form of warfare, in which the fighting armies maintain static lines of fortifications dug in the ground, called trenches. Trench warfare arose from a revolution in firearms. There were periods of trench warfare in the Civil War (1861-1865) and the Russo-Japanese War of 1904-1905, but it reached its peak of brutality and mortality on the Western Front of the First World War. They reached a depth of between one and two meters, and connected with others for greater mobility of the battle blocks.
