​Which of the following is a common element in an MS Word 365 document's header or footer?​

Correct option is C

Page numbers: A very common element in headers and footers to help readers easily navigate the document.

While the other options might be used within a document, they are less typical for headers and footers:

• Document title: Often appears in the document's title bar or as a heading within the document itself, rather than in the header/footer.
• Bullet points: Used within the main body of the text for lists, not usually in headers/footers.
• Font color: While you can change the font color within a header/footer, it's not a defining element like page numbers.