6.b.    A company has a number of employees. The attributes of EMPLOYEE include Employee_ID (identifier), Name, Address (A composite attribute), and birthdate. The company also has several projects. Attributes of PROJECT include Project_ID (identifier), Project_name, and Start_Date. Each employee may be assigned to one or more projects, or may not be assigned to a project. A project must have at least one employee assigned to it, and may have many employees assigned to it. An employee’s billing rate may vary by project, and the company wishes to record the applicable billing rate (Billing_Rate) for each employee when assigned to a particular project.