假定学生关系是S(SNo, SName, Sex, Age),课程关系是C(CNo, CName, Teacher),学生选课关系是SC(SNo, CNo, Grade)。要查找选修4门以上(含4门)课程的学生总成绩（不统计不及格的课程），正确的SQL语句是(  )。
A、SELECT Sno, SUM(Grade) FROM SC
WHERE Grade>=60 
GROUP BY Sno
HAVING COUNT(*)>=4 
B、SELECT Sno, COUNT(*), SUM(Grade) FROM SC
GROUP BY Sno
HAVING Grade>=60 and COUNT(*)>=4
C、SELECT Sno, COUNT(*), SUM(Grade) FROM SC
WHERE Grade>=60 
GROUP BY Sno
HAVING COUNT(*)>=4 
D、SELECT Sno, SUM(Grade) FROM SC
WHERE Grade>=60 and COUNT(*)>=4
GROUP BY Sno