Suppose you are creating a database to help a university keep track of its course offerings. You might have the following entities in your database, since they are distinct items in real life that are related to each other in important ways: course, classroom, professor, and department. Draw an ER diagram with a box for each of these four entities and arrows between the boxes labeled with the relationships they denote. (Don’t worry about what fields each of these entities should have for now.) See the example ER diagram in your textbook.