The correct option is C. SFTP. Detailed Explanation 1. Understanding the Protocols: - HTTP (Hypertext Transfer Protocol): This is the foundation of data communication on the web. It is primarily used for transferring web pages and does not provide any encryption, making it insecure for transferring sensitive data. - FTP (File Transfer Protocol): This protocol is used for transferring files over a network. However, it does not encrypt the data being transferred, which means that any sensitive information can be intercepted by malicious actors. - SFTP (SSH File Transfer Protocol): This is a secure version of FTP that uses the SSH (Secure Shell) protocol to encrypt the data being transferred. This ensures that the files are securely transmitted over the network, protecting them from eavesdropping and tampering. - SMTP (Simple Mail Transfer Protocol): This protocol is used for sending emails. While it can be secured with TLS (Transport Layer Security), it is not designed for file transfer. 2. Why SFTP is the Correct Answer: - Security: SFTP encrypts both the commands and the data, providing a secure channel over an insecure network. This is crucial when transferring sensitive files, as it prevents unauthorized access. - Functionality: SFTP not only allows for file transfer but also supports file management capabilities such as resuming interrupted transfers, directory listings, and remote file removal. - Use of SSH: SFTP operates over the SSH protocol, which is widely recognized for its strong security features, including authentication and encryption. 3. Why the Other Options are Incorrect: - A. HTTP: While HTTP is essential for web communication, it does not provide any security features. Sensitive data transferred over HTTP can be easily intercepted, making it unsuitable for secure file transfers. - B. FTP: Although FTP is designed for file transfers, it lacks encryption. This means that any data sent via FTP can be captured in plaintext, exposing sensitive information to potential attackers. - D. SMTP: SMTP is specifically for sending emails, not for transferring files. While it can send attachments, it is not a file transfer protocol and does not provide the same level of functionality or security as SFTP. Summary of Key Points

• SFTP is the secure protocol for transferring files over a network, utilizing SSH for encryption.
• HTTP and FTP do not provide security for sensitive data transfers.
• SMTP is not designed for file transfers but for sending emails.
• Always choose protocols that ensure data security, especially when handling sensitive information.

Revision Summary

• SFTP is the secure choice for file transfers due to its encryption.
• HTTP and FTP lack security features, making them unsuitable for sensitive data.
• SMTP is for email, not file transfer.
• Always prioritize security in data transmission protocols.