error/qtype opaque/onequestionperpage
From MoodleDocs
One opaque question per page
Currently only one Opaque question is allowed per page.
To quickly set a quiz to display one question per page, click 'Update this quiz'. Under the display section change 'Questions per page' to 1 and save the quiz.
You may also add questions to pages by selecting the quiz's edit tab, turning on 'Show page breaks' and adding page breaks between each opaque question.
