The CS department needs to store information about instructors (identified by ssn, with salary and officenumber as attributes), courses (identified by cno, with cname and time as attributes), and TAs of instructors (with name and age as attributes). Instructors perform lectures of courses; each course is associated with one and only one instructor; a TA is associated with one and only one instructor. We are not interested in what courses the TA was associated with once the instructor no longer is teaching courses. Draw an ER diagram that captures this information.