Ram said, “Sita is my paternal great grandfather’s only son’s only…

Concept: In a blood-relation puzzle, resolve a chained relation statement one link at a time, starting from the outermost ancestor named and moving inward toward the person being described, translating each kinship term — son, daughter-in-law, and so on — into an exact position on the family tree.

1. Ram's paternal great-grandfather is the male ancestor three generations above Ram on his father's side.

2. This great-grandfather has only one son — so that son must be the direct link down to Ram, i.e., Ram's paternal grandfather.

3. The grandfather's only daughter-in-law is the wife of one of his sons. Ram's father must be one of this grandfather's sons — since the great-grandfather's only son is the direct link down Ram's paternal line — and since Ram exists, Ram's father certainly has a wife. As the grandfather has only ONE daughter-in-law in total, that daughter-in-law can only be Ram's father's wife.

4. Ram's father's wife is, by definition, Ram's mother.

Cross-check: Retracing forward from the great-grandfather — his only son (Ram's grandfather) → Ram's father (necessarily one of the grandfather's sons) → the father's wife, who is the grandfather's one and only daughter-in-law — lands on the same person, confirming the identification is consistent at every step.

Result: Sita is Ram's mother.