Blood relations – grandfather’s only child → his son: Pointing to a boy, Namrata says, "He is the son of my grandfather's only child." How is the boy related to Namrata?

Introduction / Context:
We decode the chain "grandfather's only child" which identifies exactly one parent of Namrata, and then take that person's son.

Given Data / Assumptions:

• Grandfather has exactly one child ⇒ that person is Namrata's parent (father or mother).
• The boy is the son of that parent.

Concept / Approach:
Child of one's parent = sibling. Since the child is male, he is a brother of Namrata.

Step-by-Step Solution:

Verification / Alternative check:
If the only child were not a parent of Namrata, Namrata would not be a descendant of this grandfather; that contradicts the premise.

Why Other Options Are Wrong:
Cousin/uncle change branches or generations; "Son" would require Namrata to be the boy's mother; "Data inadequate" ignores the exclusivity of "only child."

Common Pitfalls:
Assuming "only child" refers to a sibling of a parent; it uniquely identifies the parent.

Final Answer:
Brother