You are implementing an Azure Data Lake Gen2 storage account. You need to ensure that data will be accessible for write and read operations both even if an entire data center (zonal or non-zonal) becomes unavailable. Which kind of replication would you use for the storage account? (Choose the solution with minimum cost)

Answer options:

A.Locally-redundant storage (LRS)
B.Zone-redundant storage (ZRS)
C.Geo-redundant storage (GRS) 
D.Geo-zone-redundant storage (GZRS)

Correct Answer: B 
Zone-redundant storage replicates the Azure Storage data in a synchronous manner across 3 Azure availability zones in the primary region. With Zone-redundant storage, the data remains accessible for write and read operations both even if a zone is not available. 
The following table describes the durability and availability by outage scenario: 

Account failover is needed for restoring the write availability if the primary region becomes unavailable.
Option A is incorrect. LRS ensures availability only if a node within a data center becomes unavailable.
Option B is correct. Zone-redundant storage replicates the Azure Storage data in a synchronous manner around 3 Azure availability zones within primary region.
Option C is incorrect. GRS is not a cost-effective method. ZRS will be a more suitable option in the given scenario.
Option D is incorrect. GZRS will also ensure availability but it is not the redundant method with minimum cost. ZRS will achieve the goal in the given scenario.
Reference: 
To know more about Azure Storage Redundancy, please visit the below-given link: 

https://docs.microsoft.com/en-us/azure/storage/common/storage-redundancy