[tensor]

A does not mean "competent" in the US. Grades are curved so that only a few students get A's. It has nothing at all to do with what the student knows either. Hell, I remember some university classes explicitly assigning grades this way: a a measure of you relative to your peers. People generally don't get 4.0's either.

[lacksconfidence]

depends on the university. Many universitys do not use a curve for grading. Almost every class i went to on the very first day you get a syllabus that states the total number of available 'points' that you can get for the various parts of the class, and then states how many points you need to acquire the various grades of A B or C.