Exhibit The COMMISSION column shows the monthly commission earned by the employee. Which two tasks would require subqueries or joins in order to be performed in a single step? （）

• A、listing the employees who earn the same amount of commission as employee 3
• B、finding the total commission earned by the employees in department 10
• C、finding the number of employees who earn a commission that is higher than the average commission of the company
• D、listing the departments whose average commission is more that 600
• E、listing the employees who do not earn commission and who are working for department 20 in descending order of the employee ID 
• F、listing the employees whose annual commission is more than 6000