Explanation:
Box 1: Create a single Service Bus Namespace
To begin using Service Bus messaging entities in Azure, you must first create a namespace with a name that is unique across Azure. A namespace provides a scoping container for addressing Service Bus resources within your application.
Box 2: Create a single Service Bus Topic
Single topic is less complex and more flexible solution from the client applications which submit orders. A single topic is less complex from the perspective of infrastructure management effort.
Box 3: Create a Service Bus subscription for each restaurant for which a driver can receive orders.
Topics can have multiple, independent subscriptions.
Reference:
https://docs.microsoft.com/en-us/azure/service-bus-messaging/service-bus-messaging-overview