Question: Who is the mother of Prince who wrote "Heal the World"?
Answer(s):
answer: Katherine Jackson

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:music.lyricist.lyrics_written ns:m.09bqc6 . 
?c ns:people.person.parents ?x .
?x ns:people.person.gender ns:m.02zsn .
}