Which of the following is a limitation placed on Visual Flight Rules?

The correct answer indicates that weather must be clear enough to see the aircraft's path under Visual Flight Rules (VFR). VFR is a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow pilots to see where the aircraft is going. This visibility is crucial because pilots navigating under VFR rely on visual references outside the cockpit to maintain control and direction. If visibility conditions deteriorate, such as in heavy clouds or fog, pilots cannot legally fly under VFR as they would be unable to maintain sight of the terrain and obstacles.

In contrast, the other options do not align with the specifications of VFR. For example, there is no specific 30-minute limitation on flight time under VFR, as flight duration can vary widely depending on the operation and mission, not a generic time constraint. Additionally, VFR does not restrict flight to only certain types of aircraft; virtually all general aviation aircraft can operate under VFR as long as they meet the necessary performance and operational standards. Finally, while being certified for night flying is crucial for operating in low visibility or dark conditions, VFR can be conducted during the day without night certification, assuming the weather conditions permit.