Which of the following is an example of a self-contained RNAV system?

A self-contained RNAV (Area Navigation) system is one that does not rely on external navigational aids for its operation. Among the options provided, an Inertial Navigation System (INS) qualifies as a self-contained RNAV system because it uses internal sensors to calculate the aircraft's position based on its movement from a known starting point. The INS determines the aircraft's position by measuring its accelerations and integrating this data to track its path.

In contrast, GPS, while also a navigation system, relies on external satellites. DME/DME and VOR/DME systems depend on ground-based navigational aids to triangulate the aircraft's position. Therefore, while these systems do support area navigation, they are not considered self-contained as they necessitate external sources to function effectively. The INS's ability to operate independently, utilizing only its onboard calculations, distinguishes it as the correct answer in this context.