Which flight plans would require FSS to initiate search and rescue procedures?

The choice indicating that VFR (Visual Flight Rules) and DVFR (Defense Visual Flight Rules) flight plans would require the Flight Service Station (FSS) to initiate search and rescue procedures is correct for several reasons.

VFR flight plans are used by pilots to indicate their flight intent to air traffic services but are not mandatory. However, if a pilot files a VFR flight plan and then fails to arrive at their destination or communicate, it raises a concern for their safety. Because these flight plans work based on visual navigation and flexibility, a significant concern lies in the fact that VFR pilots might encounter unexpected weather or other challenges without the safety net of air traffic control (ATC) oversight, making them more susceptible to emergencies that would necessitate search and rescue efforts.

DVFR flight plans, while similar to VFR plans, are specifically utilized in airspace where military operations are conducted. Like VFR flight plans, if a DVFR flight is unaccounted for, it may indicate a potential incident or accident, prompting the FSS to act accordingly to safeguard the pilot's safety.

In contrast, IFR (Instrument Flight Rules) flight plans are typically tracked rigorously by ATC. Pilots flying under IFR are under constant radar surveillance