[mdpopescu]

You start with a subjective criteria? Ouch. It reminds me of the time I had to do some work for a factory... every department was telling me how theirs was the most important work - with arguments.

I can make an argument for even a "write to log" line as being extremely important when something goes wrong; I have no idea how I would pick three lines out of a hundred.

[tnecniv]

If I were giving the interview (not OP), I wouldn't care which lines you picked, just how you justified it.