The Development Team is working on a real-time chatting application that will use Amazon CloudFront. This application will be based on the WebSocket protocol. Development team is concerned about the changes required to support this application.
Which is the correct statement to have WebSocket support with Amazon CloudFront for a SysOps Administrator?

Answer options:

A.WebSocket needs to be enabled globally with Amazon CloudFront.
B.WebSocket needs to be enabled while creating distribution.
C.Server needs to send an HTTP request with the upgrade protocol header.
D.Client needs to send an HTTP request with the upgrade protocol header.

Correct Answer: D
WebSocket is supported by default with Amazon CloudFront. To establish connectivity using WebSocket, clients need to send an HTTP request with an upgrade protocol header. The server responds to it, and connectivity over WebSocket protocol is established.
Options A and B are incorrect as WebSocket is supported on Amazon CloudFront by default; no additional configuration is required. 
Option C is incorrect as to establish WebSocket connectivity, a client sends an HTTP request with an upgrade protocol header to which the server responds. Servers do not initiate HTTP requests to establish WebSocket connectivity. 
For more information on WebSocket with Amazon CloudFront, refer to the following URL,
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-working-with.websockets.html