A.SELECT S# FROM SC WHERE C#="C2" AND GRADE> =(SELECT GRADE FROM SC WHERE C#="C2") B.SELECT S# FROM SC WHERE C#="C2" AND GRADE IN(SELECT GRADE FROM SC WHERE C#="C2") C.SELECT S# FROM SC WHERE C#="C2" AND GRADE NOT IN(SELECT GRADE FROM SC WHERE C#="C2") D.SELECT S# FROM SC WHERE C#="C2" AND GRADE> =ALL(SELECT GRADE FROM SC WHERE C#="C2")