Explanation

Box 1: eventgrid
To create event subscription use: az eventgrid event-subscription create Box 2: event-subscription Box 3: servicebusqueue Scenario: Azure Service Bus and Azure Event Grid Azure Event Grid must use Azure Service Bus for queue-based load leveling.
Events in Azure Event Grid must be routed directly to Service Bus queues for use in buffering.
Events from Azure Service Bus and other Azure services must continue to be routed to Azure Event Grid for processing.
Reference:
https://docs.microsoft.com/en-us/cli/azure/eventgrid/event-subscription?view=azure-cli-latest#az_eventgrid_ev