查询成绩在60分以上的学生的信息及其选课的课程号和成绩

A.select * from student，course where grade>=60

B.select student.*，cid，grade from student，sc where student.sid=sc.sid and grade>=60

C.select * from student，sc where student.sid=sc.sid where grade>=60

D.select * from student，sc where student.sid=sc.sid where student.sid=sc.sid

正确答案：select student.*，cid，grade from student，sc where student.sid=sc.sid and grade>=60