Examine the description of the EMPLOYEES table:<br /> EMP_ID NUMBER(4) NOT NULL<br /> LAST_NAME VARCHAR2(30) NOT NULL<br /> FIRST_NAME VARCHAR2(30)<br /> DEPT_ID NUMBER(2)<br /> Which statement produces the number of different departments that have employees with last name Smith?()<p> Examine the description of the EMPLOYEES table:<br /> EMP_ID NUMBER(4) NOT NULL<br /> LAST_NAME VARCHAR2(30) NOT NULL<br /> FIRST_NAME VARCHAR2(30)<br /> DEPT_ID NUMBER(2)<br /> Which statement produces the number of different departments that have employees with last name Smith?()</p>
A、A.SELECT COUNT(*) FROM employees WHERE last_name='Smith';
B、B.SELECT COUNT(dept_id) FROM employees WHERE last_name='Smith';
C、C.SELECT DISTINCT(COUNT(dept_id)) FROM employees WHERE last_name='Smith';
D、D.SELECT COUNT(DISTINCT dept_id) FROM employees WHERE last_name='Smith';
E、E.SELECT UNIQUE(dept_id) FROM employees WHERE last_name='Smith';