Examine the description of the EMPLOYEES table:Which query is valid?

SELECT dept_id, AVG(MAX(salary)) FROM employees GROUP BY dept_id;

SELECT dept_id, join_date, SUM(salary) FROM employees GROUP BY dept_id;

SELECT dept_id, join_date, SUM(salary) FROM employees GROUP BY dept_id, join_date;

SELECT dept_id, MAX(AVG(salary)) FROM employees GROUP BY dept_id;