Which of the following email headers specifies an address for mailer-generated errors, like "no such user" bounce messages, to go to (instead of the sender's address)?

• A. Errors-To header
• B. Content-Transfer-Encoding header
• C. Mime-Version header
• D. Content-Type header

Answer: (A)

When a message can’t be delivered, the system creates a bounce and needs to know where to send that delivery failure notice. The Errors-To header specifies an address for those mailer-generated errors, directing bounce messages away from the original sender and to the designated recipient instead. The other headers serve different purposes: Content-Transfer-Encoding determines how the body is encoded for transport, Mime-Version indicates the MIME version, and Content-Type describes the media type of the content. None of these control where bounce notifications go, so the Errors-To header is the one that fulfills this role.