A.1% B.2% C.3% D.4%
A.6 B.8 C.10 D.12
A.一類;二類;三類和四類四個等級 B.一類;二類;三類;四類和五類五個等級 C.一類;二類和三類三個等級 D.一類;二類;三類;四類;五類和六類六個等級