某查询语句运行后返回的结果集为:1班722班75则可能的查询语句是()
A. SELECT class, AVG(score) FROM test WHERE class<3
B. SELECT class, AVG(score) FROM test WHERE class<3 GROUP BY class
C. SELECT class, AVG(score) FROM test GROUP BY class HAVING class<3
D. SELECT DISTINCT(class), AVG(score) FROM test WHERE class<3