What should the consultant recommend to mitigation these concerns?

Universal Containers (UC) is updating the Service Cloud console app for its call center agents. Management is concerned that deploying the new app will disrupt current operations and impact customer satisfaction.

What should the consultant recommend to mitigation these concerns?
A . Deploy the configured and tested app to production, update the agent’s profile to view the app and take away access to the old app.
B . Configure the new app in a sandbox. Use a change-set to push the configuration to production for testing and training.
C . Deploy the configuration from a sandbox to production during the next Salesforce version update so the system only goes down once.
D . Configure the new app m developer org and use an unmanaged package to deploy to production.

Answer: D