If a tanker contains multi-compartments carrying different dangerous goods (e.g., Petrol and Diesel), what is the correct way to display the numbered orange-coloured plates?

1. A single plain plate at the front, and one plate with the HIN/UN for Petrol at the rear
2. Numbered orange plates showing the respective HIN/UN numbers on the sides of each compartment, and plain orange plates at the front and rear of the vehicle
3. Only plain orange plates on the sides, and numbered plates at the front and rear
4. A single numbered plate on the passenger side door only