The correct answer is C. Real-time text messaging
Step-by-step explanation:
Chat rooms are websites that allow users to send messages to others even if the other person is on the other side of the world. Due to the nature of these websites, these are used by users to know people or talk about common interests. Besides this, chat rooms differ from other websites because it implies synchronous conferencing, this implies messaging occurs in real-time because to contact any other user she/he needs to be online and messages are sent and received immediately. Thus, from the options, the main feature of chat rooms is real-time text messaging.