Answer:
(C) progressive enhancement
Explanation:
Progressive enhancement is a web design technique that first underlines the main functionality web page and then incorporates increasingly enhanced and advanced features and design levels.
This process enables the users to use and access the basic features of the web pages. These users can use any browser to access the main contents of the web page. Progressive Enhancement also offers an advanced version of the website for those with more advanced and sophisticated computer browsers or faster internet connection.
So the user can access basic features of a web sites as well as the complex features. This process first makes sure the basic intended purpose and main contents of the web site is accessible to all users before adding complex features which are supported by different browsers and devices.
Validation is a process which checks that code of the website is as per the world wide web standards and also checks that content of web pages and design of websites is being properly displayed and the site is accessible. So this is not the correct option.
Technique of altering a web site in a way that it can appear higher in the search engine results is called optimization so this is not a correct option.
