Introducing a boy, Rahul says, "He is the son of the brother of the only daughter of my maternal grandfather." How is the boy related to Rahul?

Introduction / Context:
This blood relation question involves the phrase the only daughter of my maternal grandfather and then refers to her brother and his son. You need to unpack these nested relations and finally identify how the boy is related to Rahul. Questions like this are designed to test whether you can track relations through grandparents and maternal uncles correctly.

Given Data / Assumptions:

• Rahul's maternal grandfather is his mother's father.
• The only daughter of Rahul's maternal grandfather is Rahul's mother, since she is the only daughter.
• The brother of Rahul's mother is Rahul's maternal uncle.
• The boy is the son of this maternal uncle.
• We assume a typical family tree without extra marriages or adoptions unless stated.

Concept / Approach:
Once we identify the only daughter of my maternal grandfather as Rahul's mother, the next step is direct: her brother is Rahul's maternal uncle, and the boy is that uncle's son. The son of an uncle is a cousin. Since the boy is explicitly male, he is a male cousin (often informally called a cousin brother), but in formal reasoning terms cousin is the standard label.

Step-by-Step Solution:
Step 1: Let MG be Rahul's maternal grandfather (his mother's father).Step 2: MG's only daughter is Rahul's mother, because she is the daughter on the maternal side.Step 3: The brother of Rahul's mother is Rahul's maternal uncle.Step 4: The boy is the son of this maternal uncle, so the boy is the uncle's child.Step 5: A child of one's maternal uncle is one's cousin.Step 6: Therefore, the boy is Rahul's cousin.

Verification / Alternative check:
Build an example: Let the maternal grandfather have two children: a daughter (Rahul's mother) and a son (Rahul's maternal uncle). Rahul is the child of the daughter. The uncle has his own son, the boy being introduced. The relationship between Rahul and the boy is that they share the same grandparents (the maternal grandfather and his wife) but have different parents who are siblings. This is exactly what cousin means. No consistent structure that respects only daughter and brother can make the boy into Rahul's son, father or grandfather.

Why Other Options Are Wrong:
Grandfather is impossible because the boy is clearly one generation below the uncle, not above Rahul.Son would require the boy to be Rahul's direct child, which is not suggested.Father reverses the generation and would make Rahul the son of the introduced boy, which contradicts the description.Uncle would require the boy to be a sibling of one of Rahul's parents, which is not the case; that role belongs to the boy's father.

Common Pitfalls:
Some candidates misread only daughter and assume the described daughter is some other relative, or they skip the step of identifying her as Rahul's mother. Others confuse maternal grandfather with paternal grandfather and end up placing the uncle on the wrong side of the family. Carefully anchoring maternal to the mother's side avoids this confusion.

Final Answer:
The boy introduced by Rahul is his Cousin.