How to award students full marks to a particular question irrespective of the answer (after attempts have been made)

1.  Go to the quiz and view the question page.

2.  Edit the required question and set all options to 100% - this will award full marks for the question irrespective of the answer.

3.  Go back to the quiz and click the "View xxx attempts" link.  Download a copy of the existing quiz attempts in the event you need to refer back to the original data.

4.  On the next screen click the button to "Dry run a full regrade".  Moodle will review the quiz attempts and present the results again.  The scores of students affected will be updated.

5.  Review the results and view the attempt for a few affected students to confirm that the re-grade has been applied correctly.

6.  When you're happy to go ahead with it, click the "Regrade attempts marked as needing regrading" button.