This country’s communist party was castigated by the Comintern for failing to prevent a former economics professor from taking power in the June 9 coup d’etat. Communists in this country launched the September Uprising under the leadership of operatives who were later tried in the Leipzig trial. In 1925, the League of Nations stopped a war between this country and its southern neighbor after a sentry from this country shot a soldier (15[2])chasing his dog across the border. This country was the headquarters for the IMRO, which assassinated its prime minister Aleksandar (*) Stamboliyski in 1923. The Treaty of Neuilly-sur-Seine forced this country to cede territories including Dobruja. This country’s defeat in World War I led to the abdication of its tsar Ferdinand I. For 10 points, name this Balkan country, which, along with Germany, Austria-Hungary, and the Ottoman Empire, made up the Central Powers. ■END■