Why Did World War I Transform Western Civilization So Profoundly

Why did World War I transform Western civilization so profoundly?

A) The bitter war between the anti-militaristic neighbors of Germany, France, and Britain shook the popular conceptions of politics deeply.
B) Because a vast majority of the victims were civilians, the war forever changed public perception of the acceptability of military conflict.
C) As a global conflict between socialist nations and monarchies, the war signaled the ideological divisions of the twentieth century.
D) The war generated an economic boom in Europe and the United States that marked the beginning of the so-called Roaring Twenties.
E) The mass slaughter of World War I was hard to reconcile with the claim that Western civilization was the triumph of reason and progress.