To view a student's Quiz attempt you will need to:
Click on your Quiz activity from within your LEO unit.
A link in blue will indicate how many of your students have attempted the Quiz (Attempts: 60). Click on the link.
Scroll past the reporting functionality, until you reach the 'Attempts' information. Click on the 'Review attempt' link to view an individual student's Quiz attempt. In the new window that opens you are able to review the student's response, override a mark, or leave a comment for your student to read.