Management has asked you to calculate the value 12*salary* commission_pct for all the employees in the EMP table. The EMP table contains these columns: Which statement ensures that a value is displayed in the calculated columns for all employees?（）

• A、SELECT last_name, 12*salary* commission_pct FROM emp;
• B、SELECT last_name, 12*salary* (commission_pct,0) FROM emp;
• C、SELECT last_name, 12*salary*(nvl(commission_pct,0)) FROM emp;
• D、SELECT last_name, 12*salary*(decode(commission_pct,0)) FROM emp;