Which option describes the structure of an external style sheet?

An external style sheet is a separate file that contains all the CSS code needed to style multiple web pages consistently. This separation allows for improved organization and reusability of styles across various HTML documents. By linking an external style sheet to an HTML file, you can apply the same styles to multiple pages without having to rewrite the styles in each document. This enhances maintainability since any changes made to the external stylesheet automatically reflect across all linked HTML pages, making it easier to manage site-wide design updates.

The other options describe different methods of incorporating styles into web pages. Embedding styles within HTML documents refers to internal styles, writing styles in JavaScript pertains to dynamic styling through scripting, and using in-line styles involves applying CSS directly within an HTML element. Each of these methods has its own use cases, but they do not provide the same organizational benefits as using an external style sheet.