Question: Which class of instruments is related to someone famous, and the official website  http://www.pennandteller.com  ?
Choices: timpani
autoharp
accordion
acoustic bass guitar
tambourine
conga
mellotron
trombone
double bass
hurdy-gurdy
SPARQL: SELECT DISTINCT ?e WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "class of instruments" . ?e <famous_people> ?e_1 . ?e_1 <pred:instance_of> ?c_1 . ?c_1 <pred:name> "human" . ?e_1 <official_website> ?pv . ?pv <pred:value> "http://www.pennandteller.com" .   }
Program:
function: FindAll
function: FilterStr
dependencies: 0
inputs: official website
http://www.pennandteller.com
function: FilterConcept
dependencies: 1
inputs: human
function: Relate
dependencies: 2
inputs: famous people
backward
function: FilterConcept
dependencies: 3
inputs: class of instruments
function: What
dependencies: 4
Answer: double bass