For safety reasons, it is required to install light-reflecting plates on the rear wall of a trailer or a semi-trailer. Hence, which of the following sentences is correct?

1. A It is obligatory to install one 30cm X 60cm plate plate at the center of the vehicle’s rear wall.
2. B It is obligatory to install 2 plates on a vehicle with a width of more than 150cm. The plates’ outside frame should be red and the rest yellow.
3. C Three red/yellow plates should be installed on vehicles with a width of more than 200cm.
4. D The plates will only be installed according to the requirements of the Licensing Bureau and in accordance with the directions of the chief examiner.