Which HTML element is used to specify a footer for a document or section?

The appropriate choice for specifying a footer in an HTML document or section is the <footer> element. This semantic element is designed to represent the footer of a section or document, often containing information about the author, copyright details, links to related documents, or other relevant information that usually appears at the bottom of a page or section.

Using the <footer> tag enhances the structure of HTML documents, making them more accessible and understandable to both browsers and developers. This element can encompass various types of content, including navigation links, text, or demographic data, specifically intended as supplementary information at the end of a section or page.

The other options listed do not serve this purpose: <bottom> is not a valid HTML element, <section> is used to define a thematic grouping of content rather than a footer, and <end> is also not recognized as valid HTML. Thus, the <footer> element is the most fitting and semantically correct choice for defining footers in HTML.