对于教学数据库的三个基本表：S(Sno，Sname，Ssex)，SC(Sno，Cno，Grade)，C(Cno，Cname， Teacher)，其中S为学生表，SC为学生选课表，C为课程表，则对于语句：检索至少选修LIU老师所授课课程中一门课程的女生姓名，SQL语句错误的是______。 A) SELECT Sname FROM S，SC，C WHERE S.Sno=SC.Sno AND SC.Cno=C.Cno AND Teacher=‘LIU’AND Ssex=‘F’ B) SELECT Sname FROM S WHERE Ssex=‘F’AND Sno IN (SELECT Sno FROM SC WHERE Cno IN(SELECT Cno FROM C WHERE Teacher=‘LIU’)) C) SELECT Sname FROM S WHERE Ssex=‘F’AND EXISTS (SELECT* FROM SC WHERE SC.Sno=S.Sno AND EXISTS (SELECT* FROM C WHERE Teacher=‘LIU’)) D) SELECT Sname FROM S WHERE Ssex=‘F’AND EXISTS(SELECT* FROM SC WHERE SC.Sno=S.Sno AND EXISTS (SELECT* FROM C WHERE C.Cno=SC.Cno AND Teacher=‘LIU’))