Answer:
A. Head of household.
Step-by-step explanation:
Head of household is the person who takes care of the expenses of a house and manages the house alone or with a help, but is primarily responsible for everything that involves the house where you live and with the residents of the house as well.
As we can see from the question above, Barb, besides being responsible for the care of her son with Dan, pays more than half of the cost of house maintenance. That is, Barb, is the principal responsible for the administration of the house and the son who lives with her. With this we can say that Barb is the head of the family.