Under § 26a of the Austrian Road Traffic Act (StVO 1960), what markings and lighting must be used on a bus dedicated to designated school transport (Schülerbeförderung)?

1. A green roof flashing beacon and white racing stripes on the doors
2. The official yellow square school bus warning sign (Schülertransporte-Tafel displaying children silhouettes) mounted at the front and rear, with hazard warning lights and special yellow flashing lights activated while boarding/alighting
3. No special signs are required if the driver carries an ID card
4. A red triangle mounted exclusively on the driver's side mirror