假设供应商S和供应情况SPJ的关系模式分别为：S(Sno，Sname，Status，City)和SPJ(Sno，Pno，Jno，Qty)。SQL语句 (22) 不能正确地查询出“零件号Pno等于‘P3’的供应商名Sname"，而 (23) ．能正确查询的关系代数表达式。

A．SELECT DISTINCT Sname

B．SELECT DISTmCT Sname
FROMS FROMS
WHERE EXISTS WHERE 0＜
(SELECT * (SEIECT COUNT (*)
FROM SPJ FROM SPJ
WHERE S.Sno=SPJ.SnO WHERE S.Sno=SPJ.Sno
AND SPJ.Pno= ’P3’) AND SPJ.Pno= ’P3’)

C．SELECT Sname

D．SELECT Sname
FROMS FROMS, SPJ
WHERE EXISTS WHERES.Sno=SPJ.Sno
(SELECT *AND SPJ.Pno= ’P3’)
FROM SPJ GROUP BYSname
WHERE S.Sno=SPJ.Sno
AND SPJ.Pno= ’P3’)

雷诺考特的日治疗费用仅相当于糠酸莫米松的（）。

A.25%

B.50%

C.75%

D.100%