查询平均分最高的学生学号和平均分,下列语句可以实现()
A. SELECT top 1 sno,avg(grade) FROM sc group by sno order by avg(grade) desc
B. SELECT sno,max(avg(grade)) FROM sc group by sno
C. SELECT sno,max(grade) FROM sc group by sno
D. SELECT sno,max(grade), avg(grade) FROM sc group by sno