Which tag defines a footer for a document or section?

The footer for a document or section is defined using the <footer> element in HTML. This semantic tag is specifically designed to contain footer content such as copyright information, author details, or links to related documents. Utilizing the <footer> tag enhances the structure of a webpage, providing clear contextual information to both users and search engines about the content contained within that section.

The footer can be used either for the entire document or for specific sections within a webpage, making it versatile and essential for good web design practices. By applying this tag, you ensure that your document is more accessible and better understood by assistive technologies.

The other choices do not correspond to any valid HTML tags specifically designed for creating footers, making them unsuitable for this question.