a.) General Pershing
Ever since the U.S. entered WW I in 1917, it had been sending divisions to fight in Europe in support of the major French or British units. However, later that year in 1917, President Woodrow Wilson selected General John J. Pershing to command and train The American Expeditionary Force (AEF).
In Europe, Pershing intended to maintain the independence of the AEF, however, he ended up integrating the army into Allied operations, a decision that helped to end the war with the Armistice of 11 November 1918, in which the Allies gained the victory.