What is the difference between exam schedules A, B, C and E, F?

We set several exam dates to accommodate the schedules of professionals whose availability is limited. Exam schedules A, B, and C differ only in the dates on which they’re held; all the other conditions are the same. Applicants are encouraged to submit their materials as early as possible, as the list is closed once it reaches the enrollment limit. Exam schedules E and F are the same as A, B, and C (only the dates are different); these schedules are for September enrollment.