What is the definition of VFR (Visual Flight Rules)?

The definition of Visual Flight Rules (VFR) centers around visual navigation and operating an aircraft under conditions where the pilot can see and avoid obstacles and other aircraft, relying primarily on visual references. This means that when flying under VFR, pilots utilize their sight to navigate, interpreting landmarks and terrain as necessary for safe flight. This method is particularly applicable in favorable weather conditions, where visibility is high enough for pilots to maintain visual separation from obstacles and other air traffic.

In contrast, the other options describe scenarios or rules that don't align with the fundamental aspect of VFR. Low visibility conditions involve flying in conditions where visual references are limited, which would not adhere to VFR principles. Additionally, flight conditions relying primarily on instruments would pertain to Instrument Flight Rules (IFR), where pilots navigate using instruments rather than visual cues. Lastly, the notion that VFR regulations apply only to commercial flights is incorrect, as VFR can apply to both private and commercial operations, depending on the visibility and flight conditions. Thus, the correct interpretation of VFR focuses on flying visually with reference to the terrain.