关系数据库（如MySQL），已知表t_order为订单表，有字段prod_id（产品种类id），user_id（购买用户id)，order_time（订单时间)等字段。现统计每种产品购买数量最多的前10个用户找出来，如下哪个语句是正确的？

A. select prod_id， user_id， count(*) as cnt from t_order group by prod_id，user_id having cnt <=10

B. select * from ( select prod_id， user_id， cnt， row_number() over (partition by prod_id order by cnt desc) as rn from (select prod_id， user_id， count(*) as cnt from t_order group by prod_id，user_id) a ) b where rn <=10

C. select * from ( select prod_id， user_id， cnt， row_number() over (partition by user_id order by cnt ) as rn from (select prod_id， user_id， count(*) as cnt from t_order group by prod_id，user_id) a ) b where rn <=10

D. select * from ( select prod_id， user_id， cnt， row_number() over (partition by user_id order by cnt desc) as rn from (select prod_id， user_id， count(*) as cnt from t_order group by prod_id，user_id) a ) b where rn <=10