Step-by-step Solution:

Quick Solution

To solve this complex blood relation puzzle, we need to break down Nirmal's statement piece by piece, starting from the end of the phrase and working our way to the beginning.

1. Deconstructing the Statement

Let's analyze the core phrase: "...the daughter of my wife's grandfather's only child."

1. "my wife's grandfather's only child": The "only child" of a person's grandfather must be that person's parent. So, this part of the statement refers to Nirmal's wife's parent (either her father or mother).
2. "the daughter of [my wife's parent]": The daughter of your own parent is either yourself (if you are female) or your sister. In this context, the daughter of Nirmal's wife's parent is simply Nirmal's wife herself.

Now, we can substitute this simplified meaning back into the full statement.

• The original statement is: "She is the sister of [the daughter of my wife's grandfather's only child]".
• After simplifying, this becomes: "She is the sister of [Nirmal's wife]".

2. Determining the Final Relationship

- The woman being pointed at is the sister of Nirmal's wife.
- A person's wife's sister is their sister-in-law.

The final condition in the question, "if she is not the wife of Nirmal," is consistent with our conclusion.

Final Answer: The woman is Nirmal's Sister-in-law.