You are designing a distributed sales application where different Azure services process orders, billing, payments, inventory, and shipping. These services must communicate asynchronously using XML messages. Which Azure messaging service should you recommend?

Azure Service Bus is the correct choice because it is a fully managed enterprise integration message broker that supports asynchronous messaging, including XML messages, and advanced messaging patterns like topics and subscriptions, which are ideal for distributed applications with multiple communicating services. Azure Blob Storage is incorrect because it's an object storage solution, not a messaging service. Azure Notification Hubs is designed for sending push notifications to mobile devices, not for inter-service communication. Azure Application Gateway is a web traffic load balancer that manages and routes HTTP requests, not an asynchronous messaging service.