The Treaty of Brest-Litovsk was signed by Russia, ie, a new Bolshevik government with the Central Powers in 1918 to end Russia's participation in the First World War. On February 1, 1917, Germany returned to the politics of unlimited submarine warfare, which it previously suspended under sharp criticism, from still neutral America. Fourteen Points is a statement on the principles of peace published on January 8, 1918 by American President Wilson, with the purpose of peace talks to end the First World War. After the policy of neutrality and isolationism, America entered the First World War in 1917 by announcing the war to Germany, and later to Austria, Hungary. The American public has already gained the impression of Germany as the main aggressor in Europe, and this entry America into war has marked the turning point and the event from which the Allies benefited.
The answer is: B.