What's the difference

A, B, C is the weight class.
A is vehicles 26,001lb and over (semis and other large vehicles)
B is vehicles 15,001lb to 26,000lb (straight trucks, ie, box trucks, maybe tow trucks, and rollbacks)
C is vehicles up to 15,000lb (cars, pickups, SUVs, etc)

The above is irrelevant of CDL designation, which simply means you are driving a vehicle for commercial purposes. You can have class A, B, or C with or without the CDL designation and a few states require the proper weight class of a license for things like RVs.

You didn't ask but M is a license for motorcycles.

I think Z means (or at least used to mean) airbrakes. Think most states have it combined with the CDL designation now.



EDIT - I had found this via the new posts listing, didn't realize it was in the Canadian forum.
The above is for US licenses so may not be accurate in regards to Canada.

 

Nothing, some provinces use letters others use numbers for the different classes.

 

In BC it is a class 1 with air brake endorsement, that is what you need.

 

BC's class 1 meets or beats all the other jurisdictions.