You need to provide real-time updates to the messages that users post in the chat application

You develop an HTML5 chat application.
You need to provide real-time updates to the messages that users post in the chat application.
What should you do?

A.
Use get o to obtain data updates.

B.
Use a RESTful web service.

C.
Use WebSockets.

D.
Use ajaxo to obtain data updates.