Which Cisco technology addresses management and performance concerns in a data center by unifying physical and virtual switch management?

VSO (Virtual Service Orchestrator) is not a standard or recognized Cisco technology that directly unifies physical and virtual switch management.

SVM (Service Virtualization Manager) is a concept related to managing virtualized services, not a Cisco technology for unifying physical and virtual switch management.

Cisco VM-FEX (Virtual Machine Fabric Extender) directly addresses management and performance concerns in data centers by extending the physical Cisco UCS fabric directly to virtual machines, effectively making each VM appear as a physical adapter on the fabric interconnect and unifying physical and virtual switch management.

AVS (Application Virtual Switch) is a virtual switch (like the ACI AVS), but VM-FEX is the specific technology that extends the physical switch's capabilities directly to the VMs, providing the unified management aspect.