This is a little bit of a trick question.
First off, the map of Europe was definitely redrawn by the treaty, which (among other things) ensured the creation of a Polish state. So we can exclude D.
And it's widely acknowledged by historians that the excessively harsh punishments that the treaty had for the German people fueled the rise of Hitler and National Socialism. So we can get rid of B as well.
And Part 1 of the Treaty of Versailles explicitly establishes the League of Nations, so this might exclude A, except that it's a bit of a trick answer. The United States did negotiate and sign the Treaty of Versailles, but the United States refused to ratify the treaty. For this reason, the United States was never a part of the League of Nations, which is one huge reason for why the League ultimately failed. So, technically speaking, the United States never "joined" the League, so we can exclude A.
That leaves us with C. Indeed, about seven million soldiers died in World War One, even though very few people at the time even understood why on earth anyone was fighting that war.