Introducing a woman, a boy says, "She is the wife of my grandfather's son." In this verbal reasoning blood relation question, how is the woman related to the boy?

Introduction / Context:
This is a frequently asked type of blood relation question where a person introduces someone using a phrase built around my grandfather's son. The challenge is to correctly identify who that son is and then connect the wife of that person back to the boy. Many standard exam questions assume that such a phrase refers to the boy's father unless additional siblings are explicitly mentioned.

Given Data / Assumptions:
• A boy is speaking about a woman.• He says, "She is the wife of my grandfather's son."• Grandfather refers to the boy's father's or mother's father.• In common reasoning questions, my grandfather's son is usually interpreted as the boy's father unless otherwise specified.• We assume a simple family structure where the son referred to is indeed the father of the boy to keep the puzzle solvable with a single unique answer.

Concept / Approach:
The core idea is to identify my grandfather's son. From the boy's point of view, his grandfather has at least one son, and in typical exam settings, that son is his father. Once we interpret my grandfather's son as my father, the woman described as the wife of my grandfather's son becomes the wife of the boy's father. The wife of one's father is one's mother. Therefore, the woman is the mother of the boy.

Step-by-Step Solution:
Step 1: Let G be the boy's grandfather.Step 2: The boy says my grandfather's son. In standard reasoning questions, this refers to the boy's father.Step 3: So, my grandfather's son is the boy's father, call him F.Step 4: The woman is described as the wife of this man F.Step 5: The wife of the boy's father F is the boy's mother.Step 6: Therefore, the woman is the mother of the boy.

Verification / Alternative check:
If we tried to interpret my grandfather's son as an uncle instead of the father, then the woman would be the aunt of the boy (uncle's wife). That would produce another plausible relationship, making the answer ambiguous. However, competitive exam questions of this pattern are conventionally set so that my grandfather's son means my father. This keeps a single correct answer and matches many classic solved examples where the relation is mother. Accepting this standard convention, mother is the unique intended answer.

Why Other Options Are Wrong:
Aunt: This could occur if my grandfather's son were an uncle, but the question follows the standard convention that the son is the father.Wife: Simply saying wife does not indicate whose wife; here the relationship must be described relative to the boy.Cannot be determined: Under typical exam assumptions, the reference is unambiguous enough to decide that she is the mother.Sister-in-law: A sister-in-law relation involves siblings or spouses, which does not fit the description provided.

Common Pitfalls:
A major source of confusion is overthinking how many sons the grandfather might have. While real families can have multiple sons, puzzle questions usually narrow to the simplest interpretation. If you always first test whether the described son can be the speaker's father, you often reach the intended answer quickly. Here, recognising that the wife of my grandfather's son is just the wife of my father directly leads to mother as the correct relationship.

Final Answer:
The woman is the boy's mother.