Answer:
D. 143
Step-by-step explanation:
A server that allows the entire management of an email account through more than one email client such that the clients the messages of the clients are stored on the server pending being deleted by the user, is an IMAP server
The port that the IMAP server listens to is the port number 143, therefore, the client application typically makes use of port 143 while using the TCP/IP protocol to contact the email server