What is the {royal or noble rank} for {office held by head of state} of {Kingdom of Mercia}
What royal or noble rank does the head of state of the Kingdom of Mercia hold?
 select distinct ?obj where { wd:Q105092 wdt:P1906 ?obj . ?obj wdt:P31 wd:Q355567 } 
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q105092> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1906> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q355567> } 
What illustrious or respectable rank does the head of state of the Kingdom of Mercia hold?