What is show incorrect answers once completed

If I select Show incorrect Answers once completed.
                                                   
Will it show them to the candidate prior to them resitting the test or having to watch the presentation?

ANSWER:

It will show the questions they got incorrect and what the actual answer is at the end of the lesson.

So they click submit, whether they pass or fail it should display on the screen a list of questions they got wrong and what the correct answers are in green or something like that.