How are driving licence classes categorized under Article 223(1) of the Bahrain Traffic Law Implementing Regulation?

1. Numeric grades 1 through 10 based on engine horsepower and cylinder count
2. Colour-coded bands according to the driver's years of professional experience
3. Lettered classes (a) to (d) designated by vehicle type: (a) private car, (b) private transport, (c) special use, (d) motorcycle
4. Speed-tier categories restricting drivers to specific highway lanes