Each question could get its own article
element, as it’s an "independent item of content".
If there are several questions on the same page, you could use a section
element to group them.
<section>
<h1>Quiz</h1>
<article>
<!-- question 1 -->
</article>
<article>
<!-- question 2 -->
</article>
</section>
If the question should be the heading of the article
? It’s certainly possible, but there might be cases where this not appropriate or even possible (e.g., when the question is rather complex, involving media, blockquotes, paragraphs, …). So either use the question as heading, or label the questions ("Question 1", "Question 2", …) or don’t use any heading (thanks to using article
, the outline will be correct):
<!-- question as heading -->
<article>
<h1>Where was J. R. R. Tolkien born?</h1>
</article>
<!-- label as heading, question in p -->
<article>
<h1>Question 1</h1>
<p>Where was J. R. R. Tolkien born?</p>
</article>
<!-- implicit/no heading, question in p -->
<article>
<p>Where was J. R. R. Tolkien born?</p>
</article>