This item is best solved by thinking like an operator in Prism Central: first identify whether the problem is design, control-plane state, or policy logic, then pick the option tied to that layer. The correct response is D, meaning “Delete all external subnets and VPCs which are in-use.”. The Network Controller supplies the control-plane services required for Flow Virtual Networking. Without it, Prism Central cannot build and manage overlays, gateways, and related virtual networking constructs consistently across the cluster. In lifecycle terms, Nutanix expects administrators to respect prerequisites, compatibility, and dependency order before enabling or upgrading Flow-related services.

Seen from a design perspective, the correct answer is the least ambiguous and most supportable implementation path inside Prism Central and AHV. Notice that A does not fit because it targets a different layer of the Nutanix networking and security stack than the one causing the outcome here. B does not fit because it targets a different layer of the Nutanix networking and security stack than the one causing the outcome here. Seen operationally, the correct response is the least disruptive and most deterministic one. It changes the exact Nutanix setting that governs the outcome instead of introducing workarounds elsewhere in the stack.