I don't quite follow what you mean so to sum up;
1. Comment field added to the single question answers.
2. Comment displayed on the quiz statistics page, based on their chosen answer.
3. Any answer with a 100% score should be ticked on the quiz statistics page.
4. Remove everything but the question, answer and the new comment from the quiz stats page.
So for example;
What pet do I have?
1. Dog (Comment: This is the right answer) (Score:100%)
2. Cat (Comment: This is nearly right as it has 4 legs too) (score:50%)
3. Dolphin (Comment: Completely wrong) (Score:0%)
On the stats page if they selected Cat I would see;
What pet do I have?
(# User Correct Answer) - answers box
Comment: This is nearly right as it has 4 legs too
Sorry for the confusion
What would be the cost to create that set up?