Final answer:
The 'Flatten Floor' feature is usually used to make the ground plane flat, simplifying geometry and improving the scene's appearance by eliminating distracting elements.
Step-by-step explanation:
The purpose of the Flatten Floor feature in the Edit Scene Property Manager is not explicitly mentioned in the options provided by the student. However, given common graphic design and 3D modeling practices, 'Flatten Floor' typically refers to making a ground plane in a scene perfectly flat to simplify the geometry and potentially correct disruptions in the scene caused by an uneven floor which can impact shadows and the overall look of the scene. This could be useful for eliminating unrealistic or distracting elements that might take away from the primary focus of the image, similar to how changing the shooting direction and zooming in can help clear up a distracting background in photography.