When World War I began, the participating nations believed which of the following: A) It would be a long, costly war. B) Reparations would not be part of the peace settlement. C) New weapons, although developed, would not be used. D) It would be a short, profitable war.

D) It would be a short, profitable war

Explanation:

On both sides, many believed the war was to end the same year it started. The infamous line, "We'll be back home before Christmas" was well known because it was said on both sides. This was due to Germany's Schlieffen plan but ended up failing and after was said on the Allied side after they stopped the Germans from entering Paris.

i believe the answer is d. it was not uncommon for people to faint or even convulse at these high-energy meetings.