考察下面的触发器：
CREATE OR REPLACE TRIGGER Emp_count
AFTER DELETE ON Emp_tab
FOR EACH ROW
DECLARE
N INTEGER;
BEGIN
SELECT COUNT(*)
INTO n
FROM Emp tab;
DBMS_OUT.PUT_LINE('there are now'||n||
'employees');
END;
该触发器当执行了以下的SQL语句后出错：
Delete from emp_tab where empno is equal to 7499;
下列选项哪个能修正该错误：( )
将触发器类型改为before delete的
因为触发器中不允许count，所以将count函数去掉
去掉DBMS_OUTPUT语句，因为触发器中不允许
去掉行级触发器的行级限制
