有关系S(SNO, SNAME, SDEPT,SAGE)，C(CNO, CNAME)，SC(SNO, CNO, GRADE)。其中SNO是学生号，SNAME是学生姓名，SDEPT是系别,SAGE是学生年龄， CNO是课程号，CNAME是课程名称，GRADE是成绩。查询每个系每门课程成绩前三的学生的姓名，系别，课程号，成绩。显示时按系别降序排列。（      ）
A、SELECT Top 3 S.Sno, Sdept, Cno, Grade
FROM S, SC
WHERE S.SNO=SC.SNO 
ORDER BY Sdept
B、SELECT S.Sno, Sdept, Cno, Grade
FROM S, SC
WHERE S.SNO=SC.SNO 
ORDER BY Sdept, Grade DESC
C、SELECT Top 3 S.Sno, Sdept, Cno, Grade
FROM S, SC
WHERE S.SNO=SC.SNO 
ORDER BY Sdept DESC, Grade DESC
D、SELECT Top 3 S.Sno, Sdept, Cno, Grade
FROM S, SC
WHERE S.SNO=SC.SNO 
ORDER BY Sdept , Grade DESC