______  is a multi-user system where people join channels to exchange real time

messages.

Correct option is B

1. IRC (Internet Relay Chat) is a multi-user system where people join channels (chat rooms) to exchange real-time messages.

2. It was one of the earliest forms of online chat, allowing multiple users to communicate in group settings or private messages.

3. Channels can be created for specific topics, making it a versatile platform for discussion and collaboration.

4. Listserv is a system for distributing emails to subscribers on a mailing list, not real-time messaging.

5. E-mail is used for sending messages asynchronously, and IPC (Inter-Process Communication) is used for data exchange between processes in computing, not for user chat.