Is it more useful for your grade to tell you how much of the topic you know in relation to the other students in your class (C = the average grade) or for your

Is it more useful for your grade to tell you how much of the topic you know in relation to the other students in your class (C = the average grade) or for your grade to tell you how much of the topic you know (A = you understand everything that was taught, B = you understand most of what was taught, C = you understand some of what was taught...) If you fit an entire class on a bell curve and give out 1 A, 2 B's, 4 C's, 2 D's and 1 F but the highest grade was actually a 32% would those grades be useful information? Sure, the A student knows more than the C student ... but none of the students really understand any of the material. Edit: by "how much of the topic do you know" I actually mean "how much of what was taught of the topic do you know" Ie, if the teacher taught you how to graph a linear equation and you can graph a linear equation, then you should get an A. If you can't graph a linear equation, you should get some grade less than an A. If nobody in the class can graph a linear equation, then what use is it to give an A to the person who can't graph a linear equation, but does it less wrong than everyone else?