Introducing a woman, Shashank said, "She is the mother of the only daughter of…

In a blood-relations puzzle, translate each stated relation into a family-tree link one step at a time, starting from the person named and working outward; the exact relationship term is then read off by comparing the generation and gender of the two people the puzzle connects.

1. "My son's daughter" is the only daughter of Shashank's son — that is, Shashank's granddaughter.

2. The woman being introduced is stated to be the mother of that granddaughter.

3. The mother of Shashank's son's child (who is not Shashank's own daughter) can only be the wife of that son.

4. A son's wife is, by definition, the daughter-in-law of the son's father — so the woman is Shashank's daughter-in-law.

Checking the other options:

• Daughter: Shashank's daughter is the son's sister, not his wife; a sister does not hold a parent's role over her brother's children, so she cannot be "the mother of the son's daughter."

• Sister-in-law: this relation places her among Shashank's or his spouse's siblings-by-marriage, not as a direct parent to the son's daughter, so it does not match the description.

• Wife: Shashank's wife is the mother of the son himself, not the mother of the son's own daughter; that parental role over the granddaughter belongs to the son's own spouse, not to Shashank's wife.

So the woman is confirmed as Shashank's daughter-in-law.