A.SELECT *FROM stock WHERE 单价<=15.20 .AND. 单价>=12.76
B.SELECT *FROM stock WHERE 单价<15.20 .AND. 单价>12.76
C.SELECT *FROM stock WHERE 单价>=15.20 .AND. 单价<=12.76
D.SELECT *FROM stock WHERE 单价>15.20 .AND. 单价<12.76