Introducing Sonia, Aamir says, “She is the wife of only nephew of only brother of my mother.” How Sonia is related to Aamir?

The correct answer is C. Sister-in-law.

Aamir’s mother has only one brother, and Sonia is the wife of Aamir’s mother’s only nephew. This means that Sonia is married to Aamir’s cousin. Cousins are considered to be siblings, so Sonia is Aamir’s sister-in-law.

Option A is incorrect because Sonia is not Aamir’s wife. Option B is incorrect because Sonia is not Aamir’s sister. Option D is incorrect because the data is not inadequate. The information provided is sufficient to determine that Sonia is Aamir’s sister-in-law.