What are three functions of an SDN controller? (Choose three.)
A. An SDN controller uses northbound APIs to manage applications and business logic.
B. An SDN controller functions as a gateway for the virtual machines in the SDN.
C. An SDN controller uses federated date between SDN controller domains.
D. An SDN controller uses southbound APIs to manage flow control to the switches and routers in the network.
E. An SDN controller uses federated routes between BGP autonomous systems.