Question: Which Zac Efron movie's prequel was High School Musical 2?
Answer(s):
answer: High School Musical 3: Senior Year

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.06wm0z)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.06wm0z ns:film.actor.film ?y .
?y ns:film.performance.film ?x .
?x ns:film.film.prequel ns:m.0bc5ny . 
}