Which of the following is NOT a primary component of a typical aircraft fuel system?

The correct choice indicates that landing gear is not a primary component of a typical aircraft fuel system. An aircraft's fuel system is primarily concerned with the storage, transfer, and management of fuel rather than any components associated with the landing gear, which serves an entirely different function related to aircraft support and mobility during ground operations.

Fuel selectors, fuel tanks, and fuel lines are essential components of the fuel system. Fuel tanks store the fuel necessary for flight, fuel lines carry fuel from the tanks to the engines, and fuel selectors allow the pilot to choose which tank to draw fuel from, ensuring optimal performance and fuel management. In contrast, landing gear encompasses the wheels and structures that support the aircraft on the ground and facilitate takeoff and landing, not any function related to fuel systems or fuel management.