Which setting will allow a virtual machine to have direct secure access to an RDM?

NIOC (Network I/O Control) is a vSphere feature that allocates bandwidth shares and limits across virtual network adapters, and has no role in Fibre Channel or RDM access.

NPV (N-Port Virtualization) is a Fibre Channel fabric feature used in switches to consolidate FC ports through an edge switch acting as a proxy, and does not provide per-VM RDM access.

NPIV allows a physical FC HBA port to be subdivided into multiple virtual ports (vHBAs), each with its own WWPN and WWNN. This enables a VM to communicate directly with a SAN target through its own dedicated virtual FC port, providing secure, isolated RDM access without sharing the host's physical HBA identity.

CPUID Mask is a VM setting that hides or exposes specific CPU feature flags to the guest OS for compatibility purposes, and is unrelated to storage or RDM access.