What protocol does the built-in mail server use to receive emails?

• A. IMAP
• B. SMTP
• C. Gmail
• D. POP

Answer: (B)

The key idea is understanding what each protocol does in email delivery. SMTP is the standard protocol used for transferring messages between mail servers. When a message is sent, the sending server hands it off to the recipient’s server using SMTP, so the recipient’s mailbox can be populated. POP and IMAP are for end-user access to already-received mail: POP downloads messages to a client (often removing them from the server), while IMAP keeps messages on the server and lets multiple devices access them. Gmail isn’t a protocol at all; it’s a mail service. So for a built-in mail server that is receiving emails from other servers, SMTP is the correct protocol.