Question $42$

What will the following SQL query return?

SELECT employee$\_$id FROM employees UNION ALL

SELECT employee$\_$id FROM former$\_$employees;

Retrieves all employee IDs from both 'employees' and 'former$\_$employees' tables, removing duplicates.

Retrieves all employee IDs from the 'employees' table.

Retrieves employee IDs from both 'employees' and 'former$\_$employees' tables, including duplicates.

Retrieves employee IDs from both