“C means passing, not average. If C were average, that would mean lots of barely passing (D) and failing (F) students.”
According to the US Department of Education there are 2 methods of grading with descriptions of the letter grade given. In the “Norm Referenced” system a C is described as average and should be those in the 40% to 70% class rank. D’s and F’s should encompass 40% of students (20% each).
In the “Criterion Referenced” system a C is described as fair which in my mind is a synonym for average.
If the Department of Education is stating a C is average or fair there is no way, without grade inflation, that a school should have roughly 75% of it’s graduates with a 4.0 GPA.