What does it take to get a U?

Weirdly enough, I got a U on all units of my French exam, but a D as the final grade! Doesn't seem to add up, I wonder if they've screwed up this year :s
I can tell you from experience how to get a U - you'd need to either do a really bad job of answering the questions in the paper, or run out of time before you've answered enough questions. It's pretty easy, but I wouldn't try it

Did he write in blue pen?

A friend of mine saw that she got a U for an exam and she called up the exam board and turns out she had actually got a B - a story worth sharing I think

Really? How did she find that out since he also called the exam board to see if it was a mistake but they said they couldn't tell him his results over the phone for data protection purposes.