15. Katherine and Christopher Turner were married in 2007. After a serious argument, Christopher moved out of the family home on July 22, 2021 and lived alone in an apartment for the remainder of 2021, but the parties remain married. Stephanie Turner, the nine year old daughter of Katherine and Christopher, resided for all of 2021 in the family home, where Katherine remained after Christopher left. Christopher refuses to file a joint return for tax year 2021. Assuming that Katherine seeks to use the most advantageous filing status for her 2021 return, how will she file? Married separate A Single B C Abandoned spouse D Head of household E None of the above