Was a company that employed M2 and M3 and employed M4 a production company
SELECT count(*) WHERE {
?x0 a ns:business.employer .
?x0 a ns:film.production_company .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M4
}