Any long wood may protrude from the back part of a timber transport trailer at a distance not larger than:

The question is about carrying long timber on a timber transport trailer (przyczepa kłonicowa). The load is allowed to stick out at the back beyond the trailer by no more than 5 m - answer B.

The Road Traffic Act states that when carrying long timber, the load may stick out at the back beyond a timber transport trailer by no more than 5 m. This is an exception to the general rule, according to which a load must not stick out at the back more than 2 m beyond the rear outline of the vehicle or vehicle combination - and that is exactly why answer A is wrong, and 7 m does not appear in the rules. With a timber transport trailer, these general 2 m are measured from the trailer's axle, because the long timber rests on the stakes and itself forms the connection between the vehicles. A load sticking out at the back by more than 0.5 m must be marked with white and red stripes with a total area of at least 1000 square centimetres or - which the Act allows precisely for long timber - with an orange flag or board at the end of the load; during poor visibility, a red light and a red reflector are added.

Legal basis: Art. 61 para. 6 point 2, para. 7, 8 and para. 9 point 3 of the Road Traffic Act (Prawo o ruchu drogowym)