What are HTML clay templates designed for in Liferay?

HTML clay templates in Liferay are specifically designed to combine HTML markup with Clay CSS, a design framework that streamlines the creation of user interface components. Clay is a collection of CSS, HTML, and JavaScript components that allow developers to build responsive and modern web applications efficiently. By using HTML clay templates, developers can leverage the predefined styles and components from the Clay framework, ensuring consistency across user interfaces while also enhancing productivity by minimizing the need to write custom CSS for common UI elements.

The other options pertain to functionalities that do not align with the primary use of HTML clay templates in Liferay. For instance, creating scripts for backend processing is typically handled using server-side technologies, while designing mobile applications often relies on frameworks specialized for mobile development. Implementing security protocols involves measures separate from user interface design, focusing instead on protecting applications and data. Thus, the emphasis of HTML clay templates on combining HTML with Clay CSS is what makes this option the correct choice.