The First World War resulted in the collapse of the Ottoman Empire. This also meant that the Turkish imperial history came to an end. After three years of national struggle, the Treaty of Lausanne, signed on July 24, 1923, established the new Turkish nation-state. The Treaty of Lausanne replaced the Peace Treaty of Sevres, which the Republican Turkey had never signed, and Turkey asserted its complete sovereignty over its current territory with the exception of Hatay (the district of Alexandretta), which finally (re) united with the motherland in 1939. Despite few restrictions on the Turkish Straits and some commercial and judicial privileges, the Treaty of Lausanne has served as the international recognition of the Turkish National Pact (Misak-ı Milli), which had been adopted in 1920 by the Meclis-i Mebusan, the Ottoman Parliament.

Turkey asserted its complete sovereignty over its current territory with the exception of Hatay (the district of Alexandretta), which finally (re) united with the motherland in 1939. Therefore, the correct answer is D.