Study the following diagram depicting common e$-$mail protocols. Identify the protocol depicted by the letter A$,$ that is used to send e$-$mail and the protocol depicted by the letter B that is used to retrieve e$-$mail.a$.$POP$3($Post Office Protocol version $3)$; IMAP $($Internet Message Access Protocol$)$b$.$DHCP $($Dynamic Host Configuration Protocol$)$; IMAPc.SMTP; POP$3$d$.$IMAP; POP$3$