r each of the following descriptions: construct an ER diagram with appropriate constraints on the relationship. (a) A department belongs to one company; each company operates at most four departments. (b) Each department in part (e) employs at least 3 employes; each employee works for one department. Each of the employees in part (b) may have one or more dependants, or none at all; each dependant belongs to one employee. Each employee in part (c) may or may not have an employment history; each employment history belongs to one employee. (e) (d)