question: What actor whose employer was acquired by M4 , M5 , and M6 was employed by M1 , M2 , and M3
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.actor .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
  ?x1 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M4 .
  ?x1 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M5 .
  ?x1 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M6
  }