What is the function of redundancy group 0 in a chassis cluster?

What is the function of redundancy group 0 in a chassis cluster?
A . Redundancy group 0 identifies the node controlling the cluster management interface IP addresses.
B . The primary node for redundancy group 0 identifies the first member node in a chassis cluster.
C . The primary node for redundancy group 0 determines the interface naming for all chassis cluster nodes.
D . The node on which redundancy group 0 is primary determineswhich Routing Engine is active in the cluster.

Answer: D