In which gear will a bus start moving forward in good road conditions, on a flat surface?

According to the manufacturer's recommendations, moving off in a bus should be done in the lowest gear to ensure sufficient power and prevent excessive clutch wear. In the situation shown, a sticker with the inscription "Anfahren nur im 1. Gang" is visible, which means "Move off only in 1st gear" and is an unambiguous indication of how to proceed.