Which of the Following Mechanisms Are Used for Service Discovery

Which of the following mechanisms are used for service discovery in a container environment?

A) The container platform offers a command like docker service discover which should be run within a container. The container platform offers a command like docker service discover which should be run within a container.
B) The container platform sets environment variables containing service information within the containers.
C) The container platform lists localhost ports assigned to containers in each container's / etc/services file. The container platform lists localhost ports assigned to containers in each container's / etc/services file.
D) The container platform mounts the sockets for all available services into the container's file systems.
E) The container platforms maintains DNS records which point to containers offering a specific service.