People who pass an engineering degree with only the minimum mark should get some kind of special cum laude.
(Always enjoy when that construction is actually valid, people often miss the reflexive part)
"What do you call a student who passed their medical exam with the lowest grade in their year?"
"A doctor"
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.
These days a 3 is no longer a conceded pass, it's a failure that entitles you to re-attempt your final exam.