Question 3 Design a generalization specialization hierarchy for a motor-vehicle sales company. The compuny sells motoreycles, passenger cars, vans, and buses. Assume that there are the two categories of vehicles: commercial and non-commercial. Note that each vehicle would attract a general sales tax, as well as an additional tax applicable to its category. You should determine the attributes of each entity type and indicate these attributes using appropriate notations. You should state any assumptions you make. The following are related to Questions 4-10. Consider the following database schema, where the primary keys are underlined. EMPLOYEE (Fnamc, Minit, Lname, Ssn, Bdalc, Addrsss, Scx, Salary, Supcr ssn, Dno) DEPARTMENT (Dname, Dnumber. Mgr_ssp, Mgr_start date), DEPT_LOCATIONS (Dmumber, Dlocation), WORKS_ON (Essn, Pnumber, Hours), PROJECT (Pname, Pnumber, Plocation, Dnum) DEPENDENT (Essn, Dependent name, Sex, Bdate, Relationship) where Fname signilices Girst name; Minil, micdle initial; Lname, less namp;; Ssn, Essn ars the sncial securily numbers; Super ssn is the sncial securily number of the xupervisor, Dname, Duwn, Dro, Dlocation are departmeat name, number and location (sinilarly for projects); while oher allributes have an chvious interpretation. Use Relational Algebra to answer the following queries. You may use any of the Relational Algetra operations, including the natural join. (4 marks each for the following seven questions) 4. Retrieve the name and address of all employees who work for the "Research" department. 5. Far every project located in 'Stafford', list the project number, the controll ing department manager's lasi name, address, and birh dulc. 6. Make a list of project numbers for projects that involve an employee whose last name is "Smith", either as a worker or as a munsger of the department that controls the project. 7. Retrieve the names of employees who have no depeadents. 8. Liat the names of maragen who have ar least one dependent. 9. Find all employex ciisetly supervisd by " "Jannes Born". 11. Find all employees directly supervised by those dircetly supcrvised by "Janes Barg". Would it be possible to find all enployees supervised by a given employee at all levels