— How many books do you have?

— _______________[ ]

A. I have six.

B. I can see six.

C. My book is here.

阅读下面的程序，回答问题

DATA SEGMENT

BUF DB '1234'

N=$-BUF

BCD DB N DUP(?)

DATA ENDS

CODE SEGMENT

ASSUME CS:CODE,DS:DATA

START：MOV AX,DATA

MOV DS,AX

LEA SI,BUF

MOV CX,N

LEA DI,BCD+N-1

LOOP1：MOV AL,[SI]

SUB AL,30H

MOV [DI],AL

INC SI

DEC DI

DEC CX

JNE LOOP1

MOV AH,4CH

INT 21H

CODE ENDS

END START

取消数据段的BCD存储区，将处理后的数据放回原处，应如何修改程序？