For which ancestors is Tarpan offered at Prayagraj Sangam?

Tarpan is offered for the immediate three paternal generations (father, grandfather, great-grandfather), three maternal generations (mother, paternal grandmother, etc.), maternal ancestors (grandfather, etc.), and can be extended to other relatives, gurus, friends, and even unknown souls (Sarva Pitru Tarpan) seeking peace. Performing it at the Sangam is believed to benefit all souls connected