A company wants to start using Azure with availability zones. If they have resources deployed across all regions in Azure, can they implement availability zones in all regions?

Answer options:

A.Yes
B.No

Answer – B 
Currently, availability zones are not available in all regions. You need to check first on the availability of zones in a region. 
Below is the snapshot from the Microsoft documentation. 

For more information on availability zones, please visit the below URL- 

https://docs.microsoft.com/en-us/azure/availability-zones/az-overview