单项选择题
A.仅Ⅰ B.仅Ⅰ和Ⅱ C.仅Ⅰ、Ⅱ和Ⅲ D.Ⅰ、Ⅱ、Ⅲ和Ⅳ
A.SUB AL,‘A’-0AH B.ADD AL,‘A’-0AH C.SUB AL,07H D.ADD AL,07H
A.DSEG SEGMENT WDAT EQU WORD PTR BDAT BDAT DB 12H,34H DSEG ENDS B.DESG SEGMENT BDAT DB 12H,34H WDAT = WORD PTR BDAT DSEG ENDS C.DESG SEGMENT WDAT EQU THIS WORD BDAT DB 12H,34H DSEG ENDS D.DESG SEGMENT BDAT DB 12H,34H WDAT LABEL WORD DESG EBDS