Where is the headquarters of the company which runs the Metro Blue Line in Minnesota?
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Metro_Blue_Line_(Minnesota)> <http://dbpedia.org/property/operator> ?x . ?x <http://dbpedia.org/property/headquarters> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Organisation>}
Metro_Blue_Line_(Minnesota)