What is the tertiary means of IP services?

The tertiary means of IP services refers to a specific level of communication capability in the event that primary and secondary means are unavailable. In this context, the NMT V-1 system serves as the correct choice.

The NMT (Navy Multiband Terminal) systems are designed to provide critical data transmission capabilities, with different versions offering various features tailored for specific operational needs. The NMT V-1, being identified as the tertiary method, is intended to be utilized when other communication pathways (like commercial or more advanced military systems) are not functional.

This choice highlights the importance of having multiple layers of communication options, ensuring that data can still be transmitted under challenging conditions. The other options represent different systems or versions, but they do not align with the designation of tertiary IP service means within the recognized operational hierarchy. In practical scenarios, selecting the right version of a system can significantly affect mission success, particularly in situations that demand reliable communication.