What is the most efficient way for a Salesforce Admin to roll out the new features?

Universal Containers launched their Community built on the Napili template. They would like to update the Community with Live Agent support and additional menu option for Assets .

What is the most efficient way for a Salesforce Admin to roll out the new features?
A . Deactivate the Community to make changes to the Community and reactivate with changes after testing in a Sandbox
B . Build a new Community with required features after testing in a Sandbox and deactivate the existing Community
C . Make changes to the existing Community after testing in a Sandbox and publish the Community when the changes are ready for customers.
D . Create new Community profiles with the modified features and assign them to customers when the Community is ready for customers.

Answer: A