You are designing a solution that uses Azure messaging. The system must follow a publish–subscribe pattern and avoid continuous polling. Which two choices accomplish this? (Each correct answer is a complete solution.)

Service Bus supports publish-subscribe through its topics and subscriptions. Publishers send messages to a topic, and subscribers receive copies of those messages from their respective subscriptions, fulfilling the publish-subscribe pattern. It also offers advanced features like message filtering and dead-lettering. Event Grid is a highly scalable, fully managed event routing service that uses a publish-subscribe model. It allows you to subscribe to events from various Azure services and custom sources, and then route those events to different handlers. This push-based model inherently avoids continuous polling. Event Hub is designed for high-throughput data streaming and event ingestion, not primarily for general-purpose publish-subscribe messaging between applications where individual messages need to be processed by multiple subscribers. While it can be used in some publish-subscribe scenarios, its core strength is stream processing. Queue (Azure Storage Queue or Service Bus Queue) is a point-to-point messaging service, meaning each message is typically processed by only one consumer. It does not natively support the publish-subscribe pattern where multiple subscribers receive the same message.