In Retrospect,it Is Clear That the First World War

In retrospect,it is clear that the First World War

A) accustomed political leaders to see a governmental role in coordinating economic activity as both vital and normal in meeting economic goals-but not in capitalist regimes.
B) helped to create the new military thinking of early 1916, which enabled military commanders on the Western Front to cut casualties and equipment usage while ending the debilitating system of trench warfare.
C) profoundly revived the faith of most soldiers, and civilians also, in the possibility of ending war and fostering permanent peace.
D) helped to produce structural crises which toppled the Russian, Ottoman, Austro-Hungarian, and German governments.
E) made the world safe for democracy.