The university has an approved list of possible final grades students may receive for each attempted course.  Faculty are limited to this list in the grades that they may assign each term.  The method for evaluating each student's progress in a course is at the discretion of the instructor, provided the method is fair, uniformly applied and made known to the class at the start of the term.  The university does not have an evaluation key or course grading system for the purpose of assigning final grades.