从student表中查询学生姓名、年龄和成绩，结果按照年龄降序排序，年龄相同的按照成绩升序排序，下面SQL语句正确的是： BC A select name age,score from student order by 1 desc,2; B select name,age,score from student order by age desc,score; C select name,age,score from student order by 2 desc,3 asc; D select name,age,score from student order by age,score asc;