The correct option is C Treaty of Versailles
The Allied Powers demilitarized Germany by the Treaty of Versailles to weaken its power. After the first world war Allied powers included Britain, France, Russia, Italy and the United States demilitarized Germany to weaken its power. In November 1918 Germany has to face the disarmament procurement of the Armistice and of the Treaty of Versailles. The German troops were to be decreased to 100,000 and, to limit the development of reserves, officers were to assist for twenty-five years.