A university database contains information about professors and courses. Professors are identified by social security number, or SSN and courses are identified by courseid. Professors teach courses; each of the following scenarios concerns the Teaches relationship set between courses and professors. For each of the following 5 scenarios, draw an ER diagram that describes it. Please assume that no other constraints hold.

I. Professors can teach the same course in several semesters, and each offering must be recorded and tracked.

II. Professors can teach the same course in several semesters, and only the most recent such course offering needs to be recorded. (Assume this condition applies in all subsequent scenario.) III. Every professor must teach some course. IV. Every professor teaches exactly one course (no more, no less). V. Every professor teaches exactly one course (no more, no less), and every course must be taught by some professor.