Which of the following ports corresponds to POP3?

The correct port for POP3, which stands for Post Office Protocol version 3, is 110. This protocol is primarily used by email clients to retrieve emails from a mail server. When a user checks their email using a client application, it typically connects to the email server on port 110 to fetch incoming messages.

The other ports listed serve different protocols: port 143 is associated with IMAP (Internet Message Access Protocol), which allows email clients to retrieve messages while keeping them on the server, providing more flexibility than POP3. Port 443 is utilized for HTTPS (Hypertext Transfer Protocol Secure), which secures web traffic, and port 80 is used for HTTP (Hypertext Transfer Protocol), which is the standard protocol for transferring web pages over the internet. Understanding these port assignments is crucial for troubleshooting and configuring network services involving email and web traffic.