Is it obligatory to make up the Dhuhr prayer and its Sunnah, or the Dhuhr prayer only, in the event that menstrual blood is discovered after the prayer, without remembering the time of its onset? And is the Sunnah to be made up separately, and at what time, if Dhuhr has been made up?

The Dhuhr prayer must be made up if a woman menstruates after its time has begun but before she has prayed it, and it should be made up after she becomes pure. As for the regular supererogatory (Sunnah) prayers, making them up is recommended but not obligatory, and whoever makes them up has done well.