Based on the provided reference, you can delete AR quizzes by clicking an "Option" (likely a menu item or button) which then shows a list of students and the title of the latest quiz they have taken. The video doesn't specify the exact steps after that, so further actions might be required to complete the deletion, such as selecting a quiz and then clicking a delete button.
Since the exact steps aren't completely clear from the provided context, more information about the specific interface of Accelerated Reader (AR) is needed to provide a fully comprehensive answer. You will likely need to navigate through the application to find the deletion option.
