Question: What agent in the United States of America maintains the National Register of Historic Places?
Choices: National Park Service
NBCUniversal
Academy of Television Arts & Sciences
E. W. Scripps Company
Chrysler
BBC
McDonald's
Nike
Avalon Hill
Hamburger SV
SPARQL: SELECT DISTINCT ?e WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "agent" . ?e_1 <maintained_by> ?e . ?e_1 <pred:name> "National Register of Historic Places" .  ?e <country> ?e_2 . ?e_2 <pred:name> "United States of America" .  }
Program:
function: Find
inputs: National Register of Historic Places
function: Relate
dependencies: 0
inputs: maintained by
forward
function: FilterConcept
dependencies: 1
inputs: agent
function: Find
inputs: United States of America
function: Relate
dependencies: 3
inputs: country
backward
function: FilterConcept
dependencies: 4
inputs: agent
function: And
dependencies: 2
5
function: What
dependencies: 6
Answer: National Park Service