Explanation:

In Microsoft Sentinel, each workspac e acts as a logical container for security data and analytics. When integrating Sentinel across organizations or environments-such as between Contoso and Fabrikam -each Azure subscription needs at least one Log Analytics workspace that Sentinel can attach t o. This workspace becomes the data repository for logs and analytics rules.
Therefore, Fabrikam requires a minimum of one Log Analytics workspace to onboard Microsoft Sentinel and begin collecting and analyzing data. Multiple workspaces may be used for isolation or region-specific requirements, but one is sufficient for a functional deployment.
To query and correlate data between multiple workspaces or tenants , Sentinel uses the workspace() KQL function. This function allows cross-workspace queries, lett ing you pull data from different Sentinel instances for investigation or threat correlation. For example:
union workspace( " FabrikamWorkspace " ).SecurityEvent, workspace( " ContosoWorkspace " ).
SecurityEvent
| summarize count() by Account
This KQL syntax enables cross-tenant or cross-subscription correlation when Defender or Sentinel workspaces are connected through proper permissions (e.g., Azure Lighthouse or cross-tenant data access).
# Final Answers:
* Minimum number of Log Analytics workspaces: 1
* Query element required to correlate data between tenants: workspace