有如下存储过程: DELIMITER // CREATE PROCEDURE CountProc1(IN s_genderVARCHAR(50),OUT num INT) BEGIN SELECT COUNT(*) INTO num FROM student WHEREgender = s_gender; END // DELIMITER ; 下面选项中,能对上述存储过程实现正确调用的是
A.
DECLARE @num; CALL CountProc1(in " 女 ",out @num);
B.
SET @num;CALL CountProc1(" 女 ",@num);
C.
DECLARE @num; DECLARE CountProc1(" 女 ",out @num);
D.
DECLARE @num; CALL CountProc1(" 女 ",@num);