Final answer:
The correct option is 4. Rotor. The two parts of a distributor in an aircraft engine ignition system are the stator and the rotor.
Step-by-step explanation:
The two parts of a distributor in an aircraft engine ignition system are the stator and the rotor.
The stator is a stationary part of the distributor that consists of a series of poles or windings. It generates a magnetic field that interacts with the rotor.
The rotor is a rotating part of the distributor that is connected to the engine's crankshaft. Inside the rotor, there is a rotating magnet that generates a magnetic field. As the rotor spins, it passes by the fixed windings of the stator, inducing an electric current. The stator is a stationary part that generates a magnetic field, while the rotor is a rotating part that induces an electric current.