When can an organization decommission its private cloud infrastructure hosted in its data center?

Answer options:

A.When they have a hybrid solution
B.When all of their servers are in the private cloud
C.When all of their servers are in the public cloud
D.When all of their servers are in the public or private cloud

Answer – C 
It can do when all the servers are migrated to the Azure cloud, which is a public cloud, and you have no dependency left on your private cloud ( or on-premises environment ). Then you can completely look to decommission it. 
Option A - wrong, since Hybrid solution refers to having network at both locations i.e., on-premises and Public Cloud.
Option B - wrong, since Private Cloud is defined as computing services offered either over the Internet or a private internal network.
Opton D - wrong, since Public or Private Cloud cannot be used here. 
For more information, please visit the below URL- 

https://docs.microsoft.com/en-us/azure/cloud-adoption-framework/migrate/migration-considerations/optimize/decommission

Answer – C 
It can do when all the servers are migrated to the Azure cloud, which is a public cloud, and you have no dependency left on your private cloud ( or on-premises environment ). Then you can completely look to decommission it. 
Option A - wrong, since Hybrid solution refers to having network at both locations i.e., on-premises and Public Cloud.
Option B - wrong, since Private Cloud is defined as computing services offered either over the Internet or a private internal network.
Opton D - wrong, since Public or Private Cloud cannot be used here. 
For more information, please visit the below URL- 

https://azure.microsoft.com/en-in/overview/what-is-a-private-cloud/