What person that a employer of M4 employed executive produced M1 and M2 and executive produced M3
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.producer.films_executive_produced M1 .
?x0 ns:film.producer.films_executive_produced M2 .
?x0 ns:film.producer.films_executive_produced M3 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x1 ns:business.employer.employees/ns:business.employment_tenure.person M4
}