Which Example Demonstrates Hardiness of the Family Unit

Which example demonstrates hardiness of the family unit?

A) Three of the children in the family were born with fetal alcohol syndrome due to alcohol abuse during pregnancy.
B) The mother and two of her four children were born with congenital cardiac defects that required open-heart surgery.
C) The children clean the house and make dinner every night so that the mother can care for the terminally ill father.
D) The mother has primary custody so that the children see their father every other weekend and during the summer.