Which of the following is a component that must be inspected as per 14 CFR Part 43?

The correct component that must be inspected as per 14 CFR Part 43 is the rotors and gearboxes. This regulation provides guidelines for the maintenance, preventive maintenance, rebuilding, and alteration of aircraft, and specifies which components are subject to mandatory inspections.

Rotors and gearboxes are critical parts of the propulsion and control systems in rotorcraft and need to comply with stringent safety and airworthiness standards. Inspections of these components typically include checking for structural integrity, wear, proper lubrication, and operational efficiency, as they significantly influence the aircraft's performance and safety.

Although wheel bearings, avionics, and lighting systems are also important for aircraft operation, they are generally subjected to different regulatory requirements and inspection criteria that may not be as directly specified under Part 43 as those applicable to rotors and gearboxes, particularly in terms of how they impact overall aircraft safety. Hence, the focus on rotors and gearboxes as a specific requirement under Part 43 highlights their crucial role in maintaining the airworthiness of aircraft.