question: Who was employed by M4 's distributor , employed by M1 , employed by a film distributor , and employed by M2
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:people.person .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x2 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  ?x1 a ns:film.film_distributor .
  ?x2 ns:film.film_distributor.films_distributed/ns:film.film_film_distributor_relationship.film M4
  }