What is the authenticity of the Hadith: "Fast from the sacred months and leave off," narrated by Abu Dawud, and does it mean fasting one day and breaking fast one day, or fasting two days and breaking fast two days, or fasting three days and breaking fast three days?

It was previously explained that the hadith indicates the permissibility of fasting some days of the sacred months and not fasting others, without specifying the number of days to be fasted or not fasted. The permissibility of fasting one day and not fasting the next has been established from the hadith in Al-Bukhari: "So fast one day and break your fast one day; that is the fasting of David, peace be upon him."