Answer:
Treaty: If the French, who started the war, had stayed out of treaty negotiations, the US could have more easily pushed through there less punitive plan. Germany would not have faced unrealizable actions, and their economy would not have been destroyed.
LON: The US had no place in the League of Nations. LON was a European matter. Had the US joined, there would have been an unfair balance of power, BUT US involvement in WWII would have been near instantneous.
Answer: Your answer is D! How does the source compare to other sources!
Carlolingian empire I hope this helps
Lincoln was morally opposed to slavery and politically opposed to any expansion of it; answer via Wikipedia