Question: What party is the public speaker that spoke about Energy development a part of?
Answer(s):
answer: Democratic Party

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:event.public_speaker.speeches_or_presentations ?k .
?k ns:event.speech_or_presentation.speech_topic ns:m.02mg6f . 
?c ns:government.politician.party ?y .
?y ns:government.political_party_tenure.party ?x .
}