Sing whatever you want - something with good variety is probably best: contrasts, range etc. to show them how much you can do. You also have to do: -sightreading -scales to test range -"sing a <interval> above/below this note" test -a test where you have to sing the middle note of a chord they play on the piano. I say 'chord' in the loosest sense - its likely to be a pretty horrible thing with 7ths, tritones etc! I'd do a lot of practice on this one - I wasn't expecting it and consequently probably didn't get a scholarship.