What is the maximum permissible dimension X for agricultural truck tractors?

Your answer is correct. The maximum permissible length for agricultural truck tractors in Germany is 12 meters.

This rule ensures that agricultural vehicles remain maneuverable and safe on public roads. The dimension "X" in the image refers to the total length of the tractor including attached equipment, such as plows or loaders. Exceeding this length can create hazards for other road users due to limited visibility, difficulty in turning, or longer braking distances.

Remember, for agricultural vehicles like tractors, the maximum allowed length differs from that of regular trucks or cars. The limit of 12 meters allows for long equipment attachments while maintaining road safety. This is why option 1 (12 m) is the correct and legally permitted dimension.