PREFIX ex: <http://example.org/ns#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?x
WHERE {
  ex:a ?x ex:c . ?x rdfs:subPropertyOf ex:p .
}

