Question: What is the OS grid reference of the town that, starting in 1948, is the twinned administrative body of Stuttgart?
Choices: SJ505955
SW475306
NZ495204
TR145575
SD198690
SK537610
TQ0105550700
TA279087
NS485635
TQ239709
SPARQL: SELECT DISTINCT ?pv WHERE { ?e <pred:instance_of> ?c . ?c <pred:name> "town" . ?e <twinned_administrative_body> ?e_1 . ?e_1 <pred:name> "Stuttgart" .  [ <pred:fact_h> ?e ; <pred:fact_r> <twinned_administrative_body> ; <pred:fact_t> ?e_1 ] <start_time> ?qpv . ?qpv <pred:year> 1948 . ?e <OS_grid_reference> ?pv .  }
Program:
function: Find
inputs: Stuttgart
function: Relate
dependencies: 0
inputs: twinned administrative body
backward
function: QFilterYear
dependencies: 1
inputs: start time
1948
=
function: FilterConcept
dependencies: 2
inputs: town
function: QueryAttr
dependencies: 3
inputs: OS grid reference
Answer: SJ505955