一个班级的学生分数表如下：
CREATE TABLE IF NOT EXISTS students (
s_id int(11) PRIMARY KEY,
s_name varchar(22) NOT NULL,
s_score int(11) NOT NULL
);
现要查询排名在20之后的学生信息并加入排名s_rank（不包括第20名，分数相同则并列排名，排名不间断），下列哪项查询语句正确
Aselect * from (select *,dense_rank() over(order by s_score desc) r_rank from students) st limit 20,9999;
Bselect *,dense_rank() over(order by s_score desc) s_rank from students where s_rank >20;
Cselect * from (select *,row_number() over(order by s_score desc) r_rank from students) st where st.r_rank >20;
Dselect * from (select *,dense_rank() over(order by s_score desc) r_rank from students) st where st.r_rank >20;