Pointing to a woman in the parking lot, Nirmal said, “She is the daughter of…

In a blood-relation puzzle, build the family tree strictly from the facts stated, one generation at a time. A puzzle yields a single named relationship only when the tree it describes is fully determined; if two or more family-tree configurations are equally consistent with everything stated, and they lead to different relationships, the correct conclusion is that the data given is inadequate to decide.

1. "My wife's grandfather's only child" — a grandfather's own child is a parent of the wife, so this only child is one of the wife's parents (call this parent P). The fact given is that the grandfather had exactly one child, P — it says nothing about how many children P has.

2. The woman is "the daughter of P". If P's only daughter is the wife herself, the woman is Nirmal's wife. If P also has another daughter, that daughter is a sibling of the wife, making the woman Nirmal's sister-in-law.

3. Both of these configurations — P having exactly one daughter, or P having more than one — are fully consistent with everything Nirmal said; the statement restricts only how many children the grandfather has, never how many children P has.

Checking each configuration against the options: one configuration matches 'the wife' (not offered here) and the other matches 'sister-in-law' — no single named relationship holds in both configurations at once. Only the conclusion that the relationship cannot be fixed holds true across every configuration consistent with the statement.

Since the statement never fixes whether the daughter being pointed to is the wife herself or a sibling of the wife, the woman's relationship to Nirmal cannot be uniquely determined from the given information — the answer is Data inadequate.