Ralph is not married and does not have any children. However, Ralph is a very good son and provides more than half of the cost of maintaining a very nice apartment for his mother. Which of the following filing statuses should Ralph use and why?

Single, because Ralph is not married.

Single, because Ralph does not have any qualifying children.

Head of Household, because Ralph's mother can be claimed as a dependent.

Head of Household, because Ralph's mother is a qualifying child.