Question: Among the rivers that are the tributary of Mississippi River,which one has the largest watershed area ?
Choices: Danube
Beowulf
Ohio River
Rhine
Amazon
River Thames
Hudson River
Mississippi River
Columbia River
Missouri River
SPARQL: SELECT ?e WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "river" . ?e_1 <tributary> ?e . ?e_1 <pred:name> "Mississippi River" .  ?e <watershed_area> ?pv . ?pv <pred:value> ?v .  } ORDER BY DESC(?v) LIMIT 1
Program:
function: Find
inputs: Mississippi River
function: Relate
dependencies: 0
inputs: tributary
forward
function: FilterConcept
dependencies: 1
inputs: river
function: SelectAmong
dependencies: 2
inputs: watershed area
largest
Answer: Missouri River