单选题 有如下存储过程: DELIMITER $$ CREATE PROCEDURE p (IN POINT INT,OUT grade_level CHAR(3)) BEGIN CASE WHEN POINT>=90 THEN SELECT '优秀'INTO grade_level; WHEN POINT>=80 THEN SELECT '良好'INTO grade_level; WHEN POINT>=70 THEN SELECT '中等'INTO grade_level; WHEN POINT>=60 THEN SELECT '及格'INTO grade_level; ELSE SELECT '不及格'INTO grade_level; END CASE ; END $$ DELIMITER ; 下列调用该存储过程的语句中正确的是( )