If one of your learners has failed a quiz, you can find out what questions he/she failed by following the below steps.
1) Locate the user in the list of users:
2) Open the User Card by clicking on the name, locate the course and click on the little arrow before the Course Name to see the lessons within the course:
3) Click on the little "Review Answers" icon:
4) The list opens in a pop-up window.