What are resource groups?

A、Automatically assigned groups of resources that all have the same type (virtual machine, app service, etc)
B、Based on the tag assigned to a resource by the deployment script, it is assigned to a group
C、A folder structure in Azure in which you organize resources like databases, virtual machines, virtual networks, or almost any resource
D、Within Azure security model, users are organized into groups, and those groups are granted permissions to resources