Which of the following individuals could claim Head of Household filing status?

I. A 25 year-old divorced mother of two children, both of whom resided with her for the entire tax year.

II. A 45 year-old widow whose spouse died in the prior tax year and who provided all expenses related to the principal residence of her dependent mother for the tax year.

III. A 56 year-old widow whose spouse died during the current tax year and who provided a household that is the principal residence of her 15-year-old daughter.

IV. A single male who owns his own home and provides 100% of the support for his Aunt Martha, who resided with him for the entire tax year and is his dependent.