Strasbourg (/ˈstræzbɜːrɡ/, French pronunciation: ​[stʁaz.buʁ, stʁas.buʁ]; Alsatian: Strossburi; German: Straßburg, [ˈʃtʁaːsbʊɐ̯k]) is the capital and largest city of the Alsace-Champagne-Ardenne-Lorraine (ACAL) region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace were historically predominantly Alemannic-speaking, hence the city's Germanic name. In 2013, the city proper had 275,718 inhabitants, Eurométropole de Strasbourg (Greater Strasbourg) had 475,934 inhabitants and the Arrondissement of Strasbourg had 482,384 inhabitants. With a population of 768,868 in 2012, Strasbourg's metropolitan area (only the part of the metropolitan area on French territory) is the ninth largest in France and home to 13% of the ACAL region's inhabitants. The transnational Eurodistrict Strasbourg-Ortenau had a population of 915,000 inhabitants in 2014.

Answer this question, if possible (if impossible, reply "unanswerable"): Strasbourg has an official seat in what parliament?
European