Not specifically the same but there's an adage, "C's get degrees". (I guess it's about how even if you got C's, you're still good enough to have a sheet of paper that even your class topper had?)
I always went with C is for cookie and that's good enough for me. Along with D for diploma.
But note, some schools require a C in prereqs to take further courses. And some schools may put you on academic probation/kick you out if your GPA falls below a C. So D for diploma is a sometimes grade.
But note, some schools require a C in prereqs to take further courses. And some schools may put you on academic probation/kick you out if your GPA falls below a C. So D for diploma is a sometimes grade.