A.SELECT S#,SNAME FROM S WHERE S# =(SELECT SS# FROM SC WHERE C#='C2') B.SELECT S#,SNAME FROM SC WHERE S#=SS# AND C#='C2' C.SELECT S#,SNAME FROM SC WHERE S#=SS# AND C#='C2'ORDER BY S# D.SELECT S#,SNAME FROM S WHERE S# IN(SELECT SS#FROM SC WHERE C#='C2')