Which of the following protocols is primarily responsible for sending and receiving email messages?

Simple Mail Transfer Protocol (SMTP) is the standard protocol used for sending and receiving email messages across the Internet. SMTP operates at the Application Layer of the TCP/IP model and is specifically designed for the transfer of email from a client to a server or between servers. It works by defining the rules for how email is sent, ensuring that messages reach their intended recipients. SMTP can send text-based messages, which can include attachments, by breaking them down into smaller packets. Its ability to communicate with different email servers makes it crucial for email delivery systems. In combination with other protocols like POP3 or IMAP (used for retrieving emails), SMTP forms the backbone of email communication. Why Other Options are Wrong: A) FTP (File Transfer Protocol) is used for transferring files, not emails. B) HTTP (HyperText Transfer Protocol) is used for transferring web pages and does not handle email. D) SNMP (Simple Network Management Protocol) is used for network management tasks, not email communication. E) DNS (Domain Name System) is responsible for resolving domain names to IP addresses and does not involve email transmission.