Which solution is recommended to replace a storage account queue for improved transaction processing in a multi-application environment?

The recommended solution for replacing a storage account queue for improved transaction processing in a multi-application environment is one Azure Service Bus topic. Azure Service Bus topics allow for a publish-subscribe messaging pattern that supports multiple subscribers, making it ideal for scenarios where multiple applications or components need to react to the same set of messages.

Using a Service Bus topic, messages can be sent to a single topic and delivered to multiple subscribers without the need for each application to poll or check a queue individually. This not only enhances scalability but also ensures that each application can independently process messages in real-time, allowing for better coordination across different services in a multi-application environment.

The built-in features of Azure Service Bus, such as dead-lettering, sessions, and transactional support, further improve the reliability and management of messaging between applications compared to traditional queue storage. These capabilities make it much simpler to handle complex workflows and maintain efficient communication in distributed systems.

Additionally, the other options do not provide the same level of functionality or scalability for multi-application environments. For instance, while a single Azure Service Bus queue could work for many applications, it lacks the publish-subscribe model that a topic offers. Multiple storage account queues could lead to greater complexity and challenges in managing message