The table exams was created using the following statement: 
You need to make certain that examinee_id is always defined and unique throughout the table.
What changes (if any) should be made to the table?
A.
examinee_id should also be designated PRIMARY KEY.
B.
NOT NULL should be added to examinee_id and removed from exam_id.
C.
The PRIMARY KEY should be dropped and re-created as PRIMARY KEY (examinee_id,
exam_id).
D.
NOT NULL should be added to examinee_id.
E.
Nothing needs to be done; the needed checks are already in place for this table.