Question: How many artists' works are in Muse d'Orsay?
SPARQL:
SELECT DISTINCT COUNT(?uri) WHERE { ?x <http://dbpedia.org/property/museum> <http://dbpedia.org/resource/Musée_d'Orsay> . ?x <http://dbpedia.org/property/artist> ?uri  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Artist>}