What programming standards should be followed for creating applications?

Standard W3C guidelines are fundamental for ensuring that applications are developed in a manner that promotes interoperability, accessibility, and consistent behavior across different platforms and devices. Following these guidelines allows developers to create applications that are more compatible with various web browsers and assistive technologies, which is essential for end-user accessibility. Adhering to these standards also encourages best practices in coding, contributing to the overall quality and maintainability of the application.

The other options suggest various constraints that could hinder application development. Restricting development to only proprietary languages or insisting that all applications be created in JavaScript can limit flexibility and creativity. Additionally, allowing custom languages to replace established standards could lead to fragmentation and problems with compatibility, compromising the overall integrity and usability of applications. Therefore, adherence to W3C guidelines provides a solid foundation for a more functional and universally applicable approach to application development.