A.SELECT Cno, AVG(Score) FROM SCS GROUP BY Score ORDER BY 2 ,Cno DESC B.SELECT Cno, AVG(Score)FROM SCS GROUP BY Cno ORDER BY 2 ,Cno DESC C.SELECT Cno, AVG(Score) FROM SCS WHERE Cno, DESC GROUP BY Score D.SELECT Cno, AVG(Score)FROM SCS GROU PBY, AVG(Score)ORDER BY,Cno DESC