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

C．SELECT Sname

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