Class B: 50× (1-32%-10%-8%-20%) =15 (person).

Class C: 14 (person).

So it is at most one kind;

(2) The first-class pass rate is 4750×100% = 94%;

Pass rate of class two1-8% = 92;

The pass rate of three shifts is 4850× 100% = 96%.

So the highest pass rate is Class Three.