A. The distance between the mid-point of the rear and front axis of the semi-trailer to the front of the vehicle or load

B. The distance between the rear axis of the semi-trailer to the centre of the kingpin

C. The distance between the rear axis of the semi-trailer to the front of the vehicle or its load

D. The distance from the rear axis to the front of the trailer (excluding any drawbars and/or the front axle set)