The following is a description of aspects of the ``real world'' that we want to model. The description is ``object-oriented'' but also makes sense as a colloquial description. 1. There is a class of Employees. Information about Employees includes: i. Their Employee ID, which is unique. ii. Their name. iii. Their address. iv. The set of Projects on which they work. 2. There is a subclass Managers of Employees. Information about Managers includes all that about Employees, plus a v. Level, the ``rank'' of the manager. 3. There is a class of Projects. Information about projects includes: i. The location of the project. ii. The manager of the project. Note: it is possible that two or more projects are at the same location, have the same manager, and even have the same set of employees, yet are different projects. The ``object ID'' of each project differentiates it from any other project yet is not considered ``information'' about the project. a) Design an Entity-Relationship diagram to represent the information described above. Indicate the entities, relationships, and attributes by rectangles, diamonds, and ovals, respectively. b) Design a relational schema for the same information. Indicate primary keys for your relations. Your relation schemas should be in Boyce-Codd Normal Form; if they are not, explain why your choice is appropriate. You have the option to create new attributes to serve as keys if appropriate (again, explain why it is appropriate).