A user is configuring an email client application and decides to use a TCP$/$IP suite protocol that stores all messages on the email server so that they can be synchronized across a laptop, a smartphone, and a web email client. In addition, this protocol stores the email messages on the email server until the user explicitly deletes them.

Which of the following TCP$/$IP port numbers will the client application typically access while using this protocol to contact the email server?

$21$

$80$

$110$

$143$