Discussion: Difference between Men A, Men B, Men E

Hello, I have to subscribe for the OOcup in Slovenia (5 day in July, www.oocup.com), but have some problem with cathegories. The organizers, to whom I wrote, still didn't answer to my e-mail. I live in Switzerland, and here cathegories are different. There, the organizers have cathegories M21 A, B and E. I suppose E is elite, but what about A and B? do you think the cathegory is just splitted in two because of the number of runners, or it's because they have different lenghts? Second question: what is normal lenght for M21 cathegory in this kind of event? do I have to worry about having 20km races? :)
thanks a lot!

I competed in central Europe when i lived there, and A & B are shorter the Elite ( E) and also "less " technical ( B the easiest of all 3 ).with that type of terrain( very nice and challenging), I don't think they will have more then 10-11 km for elites.

Slovenia course seetings looks like this.
Elite (E) classic - 9-11 km
A (7-9 km), also tehnical course
B (5-7km), less technical (for recreational runners).

OO.cup terrains are always something special so maybe it could be also B very technical.

Thanks a lot! well, my mother already went to Slovenia and showed me the maps, which are really technically difficult. I am really looking forward to it..sounds really nice!
thanks again!
Lee