Competitive Obedience is exactly what you would imagine - obedient and well trained dogs having their abilities tested. Obedience can be likened to dressage, or maybe gymnastics. The overall objective is to execute each exercise within a class with precision and accuracy, dog and handler working as a complete team. Thus both handlers and dogs can be penalised for errors and faults.
This class is to introduce and support newcomers to Obedience Competition. In this class incentives in the form of a toy or rewards are allowed to be carried by the handler in the competition ring and may be given to the dog at the end of an exercise or in between exercises. To compete in the Introductory Class a handler and dog must not have won three Introductory Classes and be eligible to compete in Pre-Beginners.
To compete in Pre-Beginners a handler or dog must not have won a first place in either Pre-Beginners or Beginners nor gained a third place or above in any other Obedience class (Introductory Class excepted).
To compete in Beginners a handler or dog must not have won a total of two or more First places in Beginners Class or one First place in any other Obedience class (Introductory Class and Pre-Beginners excepted).
This is the class where more experienced handlers will start with a young dog. The dog must not have won two First places in Obedience classes (Introductory Class, Pre-Beginners and Beginners excepted).
Class A is for dogs which have not won three First prizes in Classes A, B and Open Class C in total.
Class B is for dogs that have not won three First prizes in Class B and Open Class C in total.
Open to all dogs and handlers. Awards to be given to dogs competing in three award categories:
Class B and Class C.
SOURCE:- UK KENNEL CLUB WEBSITE