Stella's (58) husband, Anthony, died in 2018, and she has not remarried. Stella's mother, Marion, lives in a nursing home. Marion's only income for 2021 consisted of $17,250 in social security benefits. Stella pays the entire cost of the nursing home and more than 50% of Marion's support. Stella does not have any children, and no one else lives with her. What is Stella's correct and most favorable filing status?