What is the use of media types in CSS and how do they support responsive design?

Introduction / Context:
CSS media types and related media features are used to tailor styles to the environment in which a page is viewed. For example, a layout that looks good on a desktop monitor may need adjustments for printing or for small mobile screens. This question focuses on the basic idea of media types, which specify the kind of device or output medium that a set of style rules targets.

Given Data / Assumptions:
- CSS can distinguish between different media such as screen and print.
- Developers want to optimize the appearance of content on various devices.
- Style sheets can be linked or written with media attributes and media queries.
- The question is about media types, not about audio or video file formats.

Concept / Approach:
Media types like screen, print, and speech describe broad classes of output devices. A style sheet can be marked as print only so that it applies when the user prints a page, or screen only for normal browser viewing. Combined with media queries, this enables responsive design that adapts to device width, orientation, and resolution. The correct option must state that media types apply different styles to different media.

Step-by-Step Solution:
Step 1: Recall common media types, for example screen for monitors and print for printed pages. Step 2: Recognize that CSS can include media specific style rules using media attributes or @media blocks. Step 3: Compare options and look for one that mentions using different style rules for different devices or media. Step 4: Select the statement that correctly describes media types as a way to optimize layout for each medium.

Verification / Alternative check:
To verify, create a style sheet that hides navigation menus when printed by using a print media query. When you print the page, menus disappear, but they remain visible on screen. This behavior confirms that media types and media queries allow device specific styling. Documentation on responsive design also highlights media features as a fundamental tool for adapting layouts.

Why Other Options Are Wrong:
Option B is wrong because CSS does not provide encryption features. Option C is incorrect since server side languages are chosen independently of CSS. Option D is false because CSS files do not embed multimedia content. Option E is unrelated because file extensions for images do not control how styles are applied to different devices.

Common Pitfalls:
A common pitfall is relying only on fixed width layouts and ignoring media types, which leads to poor user experience on small screens or printers. Another issue is misusing media queries by targeting specific devices instead of general features such as width or orientation. Good practice is to design mobile friendly layouts and then refine them with media queries and appropriate media types.

Final Answer:
Media types in CSS are used to apply different style rules to different output devices, such as screen, print, or speech, so that each medium receives an optimized layout.