Which primary NAVAIDS make up the NAS?

The primary NAVAIDS that make up the National Airspace System (NAS) include VOR (VHF Omnidirectional Range) and VORTAC (VOR Tactical Air Navigational System). VORs provide aircraft with a navigation signal allowing pilots to determine their position relative to the station and follow specific flight paths. VORTAC combines the capabilities of a VOR with a TACAN (Tactical Air Navigation) system, which provides distance information in addition to the standard VOR navigation capabilities, enhancing situational awareness for both civilian and military aircraft.

The other options do not accurately describe the primary NAVAIDS as specifically as VOR and VORTAC. While NDB (Non-Directional Beacon) and DME (Distance Measuring Equipment) are valuable components of the NAS, they serve different purposes and do not provide the same breadth of navigational information as the VOR and VORTAC combination. GPS, while crucial in modern navigation, is considered a supplementary navigation system rather than a primary NAVAID like VOR and VORTAC, which have historically formed the backbone of air navigation.