A or AV is Aperture Priotety,, this is where you pick the Aperture and the camera picks: -Shutter square -Aperture

The question is asking about the Aperture Priority mode in photography. In this mode, the photographer selects the aperture (which controls the depth of field or the amount of the scene that will be in focus), and the camera automatically selects the shutter speed. The aperture is represented by the symbol "A" or "AV". Therefore, the correct answer is "Aperture".