Azure Virtual Machine Scale Sets for its ability to automatically scale the number of VM instances based on demand, ensuring high availability and scalability.

Azure Functions for its serverless architecture, which can handle unpredictable traffic efficiently without the need to manage infrastructure, but may not be the best fit for containerized applications.

Azure Kubernetes Service (AKS) for its orchestration capabilities that manage containerized applications efficiently, offering scalability and high availability, though it may require more management overhead.

None of the above, as they do not meet the scalability, availability, and cost-effectiveness requirements.

Both Azure Virtual Machine Scale Sets and Azure Kubernetes Service (AKS) for their combined capabilities in handling automatic scaling, high availability, and containerized applications management.