The licenses here depend on the prefix attached to it to differentiate the trades.
Licensees that hold multiple classifications have multiple prefixes attached to their one license number.
An "A" contractor is a General Engineering contractor.
A "B" is a General Building contractor.
A "C" contractor is a Specialty Contractor. There are 41 types of SCs, for example: C-10 Electrical, C-20 Heating & AC, C-36 Plumbing and so on.
Additionally, there are 61 "D" Limited Specialty contractors, encompassing everything from a D-59 Hydroseed Spraying to a D-29 Wood Tank contractor.
It's enough to make your head spin