What if I don't get a B in a course that I take as a pre-CS student?
If you don't earn a grade of B in your first attempt of a required pre-major course, it will be in your best interest to GRO that class. The Major Admission Committee will use your second grade to determine your admissability to the major. If you are out of GRO points, you can repeat the course without GRO. The Admission Committee will consider both of your grades, but will place more emphasis on your more recent attempt.
If you do not earn a grade of B on your second attempt of a course, you need to speak with your advisor. Although it is possible to attempt a course three times, this may have a serious impact on your eligibility to be admitted to the major.