A user wants scan-to-email functionality on a printer.

Scan-to-email functions rely on the printer sending scanned documents to an email server. CompTIA A+ identifies SMTP (Simple Mail Transfer Protocol) as the protocol responsible for sending email messages from clients to mail servers. When configuring scan-to-email, the technician must enter:

SMTP server address

Authentication credentials

Port number (25, 465, or 587)

Encryption type (TLS/SSL)

Without SMTP, the printer cannot transmit emails.

SMS (A) refers to text messaging. SFTP (C) is secure file transfer, common for scan-to-folder workflows, not email. SMB (D) is used for Windows file sharing.

Therefore, the correct protocol is SMTP.