App1 posts shipping-request messages to an Azure Storage queue that App2 currently processes. Future additional applications must be able to receive only the messages relevant to them. Which messaging solution should you recommend to enable multiple subscribers to receive relevant transactions?

An Azure Service Bus topic is the correct solution because it enables a publish/subscribe messaging pattern. Publishers (like App1) send messages to a topic, and multiple subscribers (like App2 and future applications) can receive copies of these messages by creating subscriptions to the topic. Each subscription can have filters, allowing subscribers to receive only the messages relevant to them, fulfilling the requirement for selective message delivery. Azure Data Factory pipelines are used for data integration and transformation, not for real-time messaging between applications. Multiple storage account queues would require each application to poll its own queue, and App1 would need complex logic to send the same message to multiple queues, which doesn't scale well for selective delivery. An Azure Service Bus queue is a point-to-point messaging solution where each message is consumed by only one receiver, not suitable for multiple subscribers.