what are the licence classes?
['Heavy Combination unit towing one or more additional trailers with a GVM exceeding 9,000 kg.', 'Heavy Combination (HC class) vehicle.', 'Heavy Rigid (HR class) vehicle.', 'Medium Rigid (MR class) vehicle.', 'Light Rigid (LR class) vehicle.', 'Car (C class) vehicle.', 'Moped (R-N class) vehicle.']