Is a policeman permitted to stop a vehicle which is not lawfully loaded or marked?

1. A No, a policeman is not permitted to prohibit the vehicle from driving.
2. B Yes, but only on an urban road.
3. C No, a traffic policeman may only reprimand the vehicle owner, warn him and write him a ticket.
4. D Yes, a policeman may prohibit the vehicle from driving until the freight is lawfully arranged.