检索选修4门以上课程的学生总成绩(不统计不及格的课程),并要求按总成绩的降序排列出来。正确的SELECT语句是 A) SELECT S#,SUM(GRADE)FROM SC WHEREGRADE>=60 CROUP BY S# ORDER BY 2 DESC HAVING COUNT(*)>=4 B) SELECT S#,SUM(GRADE)FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT(*)>=4 ORDER BY 2 DESC C) SELECT S#,SUM(GRADE)FROM SC WHERE GRADE>=60 HAVINC COUNT(*)>=4 GROUP BY S# ORDER BY 2 DESC D) DELECT S#,SUM(GRADE)FROM SC WHERE GRADE>=60 ORDER BY 2 DESC CROUP BY S# HAVINC COUNT(*)>=4