I believe the answer is:
I. Disabled workers
III. Family members of deceased workers
Social security tax tend to given to the citizens who experience a certain level of hardships that prevent them from obtianing highest career potential like normal citizens.
Even though some of them might be laid off due to external circumstances, Laid off workers also include a group of people who got laid off due to unproductivity and misbehaviours. Which is why they are considered to be lower in priority comapred to disabled workers and deceased family members.