Question: Gau East Prussia was formed in 1933 in Nazi Germany initially as a district within the Free State of Prussia, in 1939, East Prussia expanded following the annexation of which location, that was defined by the Treaty of Versailles in 1920 and refers to the most northern part of the German province of East Prussia, when as Memelland it was put under the administration of the Council of Ambassadors?
Sentence (from "Gau March of Brandenburg"): After the war, the territory of the former Gau became part of the state of Brandenburg in East Germany except one of beyond Oder-Neisse line, which was given to People's Republic of Poland.
Relevant evidence: No