What makes this a strong certification question is that several answers look technically related, but only one aligns with the exact behavior of Flow networking or Flow security. The correct response is B, meaning “Mismatch in ERP configuration in user and Transit VPC”. A Floating IP is the normal mechanism for exposing a workload in an overlay-backed VPC to external clients. It preserves internal VM addressing while publishing a reachable external address through the VPC’s north-south path. Externally Routable Prefixes determine which overlay prefixes are advertised beyond the VPC. If the ERP does not cover the workload subnet, upstream devices never learn a valid return path, even when the local VPC appears healthy. Operationally, Flow Virtual Networking should be checked from the control plane outward: gateway health, peering state, route advertisement, ERP coverage, external path, and MTU when encapsulation is involved. By contrast, A does not fit because it targets a different layer of the Nutanix networking and security stack than the one causing the outcome here. C addresses exposure of a single VM, not the broader routing or security behavior under discussion. Seen operationally, the correct response is the least disruptive and most deterministic.