为自己加油

现有表 student 包含学号(sid)、课程编号(course)和成绩(score)等字段，若想费查询所有课程总成绩大于 600 分的学生，并按总成绩降序排序，要求列出学号和总成绩，以下语句能实现的是？

A.select sid,sum(score)from student where sum(score)>600 group by course order by sum(score)desc.
B.select sid,sum(score)from student group by course having sum(score)>600 order by sum(score)dese:
C.select sid,sum(score) from student where sum(score)>600 group by sid order by sum(score)desc:
D.select sid,sum(score) from student group by sid having sum(score)>600 order by sum(score) desc;