At what maximum speed are you allowed to drive on the road beyond these signs if you are hauling another passenger car?

In the photo the road comes out of a forest, and on the right there are sign E-18a "end of town" with the name Szczecin crossed out and sign D-43 "end of built-up area". Beyond these signs, when towing another passenger car, you may drive at no more than 60 km/h - answer B. Answer A (30 km/h) is the limit for towing in a built-up area, and C (90 km/h) is the general limit outside built-up areas, which does not apply when towing.

The Road Traffic Act states that a driver may tow a power-driven vehicle only on condition that the speed of the towing vehicle does not exceed 30 km/h in a built-up area and 60 km/h outside it, and the Regulation on road signs and signals states that sign D-43 marks the exit from a built-up area. A combination of two linked cars is long and heavy and brakes less well, and a tow rope or a rigid tow bar leaves no room for sudden movements, so the limit is lower than for a single car. Beyond sign D-43 you accelerate to no more than 60 km/h, keep a steady speed and signal your intention to brake early, so that the driver of the towed car has time to react.

Legal basis: Art. 31 para. 1 point 1 of the Road Traffic Act (Prawo o ruchu drogowym); § 58 para. 3 of the Regulation on road signs and signals