The correct option is D Saarland
Under the Treaty of Versailles, the highly industrialized Saar Basin, including the Saar Coal District (German: Saarrevier), was to be occupied and governed by the United Kingdom and France under a League of Nations mandate for a period of fifteen years. Its coalfields were also to be ceded to France. Hence, Option A is correct. Germany was forced to return Alsace-Lorraine to France. Posen was part of the Free State of Prussia within Weimar Germany from 1918 but was dissolved the following year when most of its territory was ceded to the Second Polish Republic by the Treaty of Versailles, and the remaining German territory was later re-organized into Posen-West Prussia in 1922.to the Treaty of Versailles, the Rhineland, a strip of land inside Germany bordering on France, Belgium and the Netherlands, was to be de-militarised. That is, no German troops were to be stationed inside that area or any fortifications built. Hence, these are incorrect.