Which three statements inserts a row into the table?（）

• A、INSERT INTO employees   VALUES ( NULL, ‘John’,‘Smith’);
• B、INSERT INTO employees( first_name, last_name)   VALUES(‘John’,‘Smith’);
• C、INSERT INTO employees   VALUES (‘1000’,‘John’,NULL);
• D、INSERT INTO employees(first_name,last_name, employee_id)   VALUES ( 1000, ‘John’,‘Smith’);
• E、INSERT INTO employees (employee_id)   VALUES (1000);
• F、INSERT INTO employees (employee_id, first_name, last_name)   VALUES ( 1000, ‘John’,‘’);