Sidney and Angelene were married in 2016. During 2020, they were both employed, each earning $132,000 for the year. They discovered that there was a significant tax savings if they could file as single taxpayers and thus arranged a vacation trip and a divorce before the end of the year. Early in 2021 they remarried. What is their filing status for for 2020? You might want to look up Rev. Rul. 76-255.