Which protocol is used for file transfer over the Internet?

The correct choice for file transfer over the Internet is the File Transfer Protocol, commonly known as FTP. This protocol is specifically designed to facilitate the transfer of files between computers on a network.

FTP operates on a client-server model and uses two separate channels for communication: one for commands and the other for transferring the data itself. This separation helps manage the various aspects of the file transfer process effectively. Additionally, FTP can support both binary and ASCII file transfers, making it versatile for different types of files.

In contrast, other protocols serve different purposes: HTTP is primarily used for transferring web pages and associated content, SMTP is focused on sending emails, and Telnet provides a way to access network devices or remote servers. Therefore, while these other protocols play significant roles in networking, FTP is specifically designed for the efficient and reliable transfer of files, which makes it the correct answer in this context.