Question: NSYNC and Boyz II Men famously represent which vocal music style?
Choices: free improvisation
country pop
psychedelic soul
progressive house music
psychedelic trance
boy band
contemporary R&B
a cappella
acid jazz
soul music
SPARQL: SELECT DISTINCT ?e WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "vocal music" . ?e <famous_people> ?e_1 . ?e_1 <pred:name> "NSYNC" .  ?e <famous_people> ?e_2 . ?e_2 <pred:name> "Boyz II Men" .  }
Program:
function: Find
inputs: NSYNC
function: Relate
dependencies: 0
inputs: famous people
backward
function: FilterConcept
dependencies: 1
inputs: vocal music
function: Find
inputs: Boyz II Men
function: Relate
dependencies: 3
inputs: famous people
backward
function: FilterConcept
dependencies: 4
inputs: vocal music
function: And
dependencies: 2
5
function: What
dependencies: 6
Answer: a cappella