You want each employee whose salary is the maximum within their own department. Which correlated form is correct?

-- Goal: keep only rows that are the dept max -- Option A SELECT e.* FROM emp e WHERE e.salary = (SELECT MAX(x.salary) FROM emp x WHERE x.dept_id = e.dept_id); -- Option B SELECT e.* FROM emp e WHERE e.salary >= ALL (SELECT x.salary FROM emp x); -- Option C SELECT e.* FROM emp e WHERE e.salary = (SELECT MAX(x.salary) FROM emp x); -- Option D SELECT e.* FROM emp e WHERE EXISTS (SELECT 1 FROM emp x WHERE x.salary > e.salary);