You will deploy Azure Container Instances for an application composed of two containers: an application container and a validation container that monitors the application by sending requests and awaiting responses after each transaction. Ensure both containers are scheduled together and may communicate only over ports that are not exposed externally. What should you include in the deployment?

A container group is the correct choice because it schedules and runs a collection of containers on the same host machine, sharing resources like storage, network, and lifecycle. This allows the application container and validation container to communicate efficiently via localhost on unexposed ports, fulfilling the requirement for internal-only communication. Application security groups (ASGs) and Network security groups (NSGs) are used to filter network traffic to and from Azure resources, but they don't group containers for co-scheduling or shared networking within a single host. Management groups are used for organizing subscriptions and applying governance policies, not for container orchestration.