出自:Oracle认证
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements insert 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', 'smith');
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','');
Which two statements are true if a NullPointerException is thrown on line 3 of class C？（） 
Which statement is correct about the database?（）