What is an example of a protocol used in Internet communications?

All the listed options are examples of protocols used in Internet communications, which is why the correct choice is all of the above.

Internet Control Message Protocol (ICMP) is a key component of Internet Protocol (IP) communications, primarily used for sending error messages and operational information. For instance, it is used in the "ping" utility, which checks connectivity between hosts.

Remote Desktop Protocol (RDP) is a protocol developed by Microsoft that allows users to connect to another computer over a network connection, providing a graphical interface to the remote system.

Internet Message Access Protocol (IMAP) is a standard protocol used by email clients to retrieve emails from a mail server, allowing users to manage their emails more effectively across different devices.

Since each of these protocols serves essential functions in Internet communications, the correct answer encompasses all of them, highlighting the interconnected ecosystem of protocols that facilitate various aspects of network communication.