How common is a must-pass-final requirement?
If someone argued that case (a) was "rare" in higher education, respond by:


asking for the data they used to come to that conclusion
determine if sample size is large enough to make any reliable conclusions
determine what 'rare' means
measure if the number of pass/fail final exams is greater than or less than the rare threshold


If they don't have data, then respond by saying that their personal experiences probably do not represent a national average.