Here's a breakdown:
* A: The easiest level, often for beginners.
* B: Slightly more challenging, but still suitable for less experienced riders.
* C: A higher level requiring more control and accuracy.
* M: Stands for "Medium", a higher level of dressage.
* S: Stands for "St. George," a very challenging test with difficult movements.
* G: Stands for "Grand Prix," the highest level of dressage, with complex and demanding movements.
The letters come from the standardized dressage tests developed by the Fédération Equestre Internationale (FEI). They ensure consistency and allow riders to progress through the levels systematically.
If you're interested in learning more about dressage tests and the FEI system, you can find information on the FEI website or from your local equestrian organization.