You administer an Azure SQL Database that runs in the S0 service tier. The database stored mission-critical
data.
You must meet the following requirements:
minimize costs associated with hosting the database in Azure
minimize downtime in the event of an outage
protect the database from unplanned events
What should you do?

A.
Implement a secondary database in the paired region.

B.
Ensure that a secondary databases are online and readable at all times.

C.
Create a continuously replicated copy.

D.
Use backups in a geo-redundant Azure storage (GRS) location.

Explanation:
https://docs.microsoft.com/en-us/azure/storage/storage-redundancy#geo-redundant-storage