Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) 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',")