Question: You would like to use Bookmarks to navigate a PDF, but the Bookmarks panel is not available. Why would that panel be unavailable?

1. The PDF does not contain any articles.
2. You are viewing the PDF in a web browser.
3. The file creator did not give the article a title.
4. You are viewing the PDF in Adobe Reader.

Answer: The correct answer of the above question is Option B:You are viewing the PDF in a web browser.