question: What is the relationship between SDN (Software Defined Networking) and NFV (Network Function Virtualization)? option 1: SDN and NFV are unrelated concepts option 2: SDN and NFV have similar goals and can enhance each other option 3: NFV replaces SDN in network management option 4: SDN requires NFV to operate efficiently option 5: SDN and NFV compete with each other in the networking industry 