Which protocol is primarily used for transferring files on the World Wide Web?

The primary protocol used for transferring files on the World Wide Web is the Hypertext Transfer Protocol (HTTP). HTTP is designed specifically for transmitting hypertext documents, such as HTML files, which are the building blocks of web pages. When you access a website, your browser sends an HTTP request to the web server, which then responds with the requested web page, allowing users to view content online efficiently.

While File Transfer Protocol (FTP) is also used for file transfers, it serves a different purpose and is generally not used for webpage content delivery on the web itself. Instead, FTP is often used for the transferring of files between servers and clients, but it does not handle the browsing experience or the structure of the World Wide Web as HTTP does.

Protocols such as Simple Mail Transfer Protocol (SMTP) and Post Office Protocol (POP) are specifically designed for email transmission and retrieval, respectively, and are irrelevant to file transfers on the web. Therefore, HTTP stands out as the appropriate choice for web file transfers, making it the correct answer in this context.