What kind of jobs can you get with a class B CDL?
Freight, construction, oilfields, municipal jobs, bus driver.
Not sure what you mean, exactly. Class A is considered the "higher" classification, yes. If you have a Class A CDL, you can operate vehicles requiring that class of licence or any class below that. You could operate a vehicle requiring a Class B CDL, for example, but a driver with a Class B CDL wouldn't be permitted to operate a combination requiring a Class A CDL.
You need either a Class C or Class B CDL, depending on the vehicle's weight. If it's a vehicle with a Gross Vehicle Weight Rating of 26,000 lbs. or less, you need a Class C CDL with passenger endorsement. If it's a vehicle with a GVWR of more than 26,000 lbs., you need a Class B CDL with passenger endorsement.