Question: What home of President Barack Obama is the place that selected Vincent C. Gray to hold public office?
Answer(s):
answer: Washington, D.C.

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.02mjmr)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.02mjmr ns:people.person.places_lived ?y .
?y ns:people.place_lived.location ?x .
FILTER(NOT EXISTS {?y ns:people.place_lived.end_date ?sk0} || 
EXISTS {?y ns:people.place_lived.end_date ?sk1 . 
FILTER(xsd:datetime(?sk1) >= "2015-08-10"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:people.place_lived.start_date ?sk2} || 
EXISTS {?y ns:people.place_lived.start_date ?sk3 . 
FILTER(xsd:datetime(?sk3) <= "2015-08-10"^^xsd:dateTime) })
?x ns:government.governmental_jurisdiction.governing_officials ?c .
?c ns:government.government_position_held.appointed_by ns:m.07t0z5 . 
}