Which part of an email message exchange is NOT inspected by the POP3 and IMAP proxies?

Which part of an email message exchange is NOT inspected by the POP3 and IMAP proxies?

Question:

Which part of an email message exchange is NOT inspected by the POP3 and IMAP proxies?

Options:

TCP connection

File attachments

Message headers

Message body

Correct Answer

The Correct Answer for this Question is

TCP connection