The answer is: 4) Cross-generational family.
A cross-generational is basically where different generations take care of the younger generation.
For example:
Jessie and Michal are both over 70. They are permanent guardians of their grandchildren.
Looking that the example, I can identify that this is a cross-generational family because Jessie and Michal are a different generation than their grandchildren.
I hope this helps! :)
-LizzyIsTheQueen