Question: What country in NATO has Sofia as its capital?
Answer(s):
answer: Bulgaria

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.059dn)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.059dn ns:organization.membership_organization.members ?y .
?y ns:organization.organization_membership.member ?x .
?x ns:location.country.capital ns:m.0ftjx . 
}