Which protocol operates at the application layer and is used for secure web…

The correct answer is HTTPS because it stands for Hypertext Transfer Protocol Secure, which operates at the application layer and encrypts data transmitted between a web browser and a server. This encryption ensures secure communication, protecting sensitive information like passwords and credit card details from interception during web browsing. HTTP (Option A) operates at the application layer but lacks encryption, making it insecure for sensitive transactions. FTP (Option C) is used for file transfers rather than web browsing, and SMTP (Option D) is designed specifically for sending emails. Therefore, HTTPS is the only protocol listed that combines application layer functionality with security features essential for safe web browsing.