Question: Which album is in the genre of opera?
Choices:
Richard Strauss
Jesus Christ Superstar
Barcelona
Hollywood
Ralph Vaughan Williams
John Cage
Robert Schumann
Toto
Dmitri Shostakovich
The Velvet Underground
Answer: Barcelona
SPARQL: SELECT DISTINCT ?e WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "album" . ?e <genre> ?e_1 . ?e_1 <pred:name> "opera" .   }
Program:
function: Find
inputs: opera
function: Relate
dependencies: 0
inputs: genre
backward
function: FilterConcept
dependencies: 1
inputs: album
function: What
dependencies: 2