Does the 50 km/h speed limit apply 24 hours a day in built-up areas?

In the photo there is a road entering a town; on the right there is a white rectangular sign with a black outline of buildings - D-42 "built-up area". The 50 km/h speed limit applies in a built-up area around the clock - answer A.

The Road Traffic Act states that the speed limit for a vehicle or vehicle combination in a built-up area is 50 km/h, and the Regulation on road signs and signals states that sign D-42 marks the entry to a built-up area. Until 2021, at night, from 23:00 to 5:00, the limit was 60 km/h; this rule was repealed, and since 1 June 2021 the 50 km/h limit has applied around the clock, with no exceptions for certain hours. Answers B and C refer to time frames that do not exist - B reverses the old night-time rule, and C invents a limit from dusk to dawn. The limit may be changed by B-33 signs in both directions: lowered near schools, raised on wide main roads. Remember that exceeding the speed limit by more than 50 km/h in a built-up area - that is, driving at more than 100 km/h where the limit is 50 - ends with the retention of the driving licence for 3 months, also at night on an empty street.

Legal basis: Art. 20 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym); § 58 para. 3 of the Regulation on road signs and signals