查询全体学生的情况，查询结果按所在系升序排列，同一系中的学生按年龄的降序排列（）

A.select * from student order by depart，age desc

B.select * from student order by depart and age desc

C.select * from sc order by depart，age desc

D.select * from sc order by depart and age desc

正确答案：select * from student order by depart，age desc