Which of the following vehicles can you overtake when you're riding a light four-wheeled vehicle (microcar, quad) on the road, once you go past this sign?

The B-25 'no overtaking' sign prohibits drivers of motor vehicles from overtaking multi-track motor vehicles. A moped, as a single-track vehicle, is not covered by this prohibition. Therefore, when driving a light quadricycle, it is legal to overtake a moped on the section of road beyond this sign.