What was a production company whose employee executive produced M1 's sequel
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.production_company .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
?x1 ns:film.producer.films_executive_produced ?x2 .
?x2 ns:film.film.prequel M1
}