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', ' ');