Overlay Transport Virtualization （OTV） provides an overlay that enables Layer 2 connectivity between separate Layer 2 domains， while keeping these domains independent and preserving the fault isolation， resiliency， and load-balancing benefits of an IP-based interconnection. Which statements are true about OTV Adjacency Server？（）

• A、 Adjacency Server is required when OTV is deployed with unicast-only transport.
• B、 Adjacency Server is required when OTV is deployed with multicast-enabled transport.
• C、 Each OTV device wishing to join a specific OTV logical overlay needs to first register with the Adjacency Server.
• D、 Each OTV device trying to join a specific OTV logical overlay needs to be configured as an Adjacency Server.