What must a driver do to legally leave their car idling unattended?

• Turn off the engine and lock the ignition.
• Remove the key from the ignition and set the brake.
• Turn the front wheels to the curb or side of the road.
• All of the above.
  Explanation:

  "It is illegal for any driver to permit their car to stand idling unattended without turning off the engine, locking the ignition, removing the key from the ignition, and setting the brake, and when standing on any grade, without turning the front wheels to the curb or side of the road."