Image Dust Off Reference Photo
Explanation: This menu allows to create a reference picture for dust removal in image processing: A picture of a plain white or grey area will show spots due to dust as deviation of the smooth area around and can be used to remove the little spots on other pictures.
This works only with Nikon‘s software Capture.
Tips: I never use this menu. If you do not use Nikon‘s software you cannot use the reference picture anyway and every good image processing program has also reasonable tools to remove dust, if needed for several pictures in one go.