If B says that his mother is the only daughter of A’s mother, then what is the relation of A with B.

Work it out step by step. B's mother is the only daughter of A's mother. So A's mother has exactly one daughter, and that daughter is B's mother. That makes B's mother A's sister, since both are children of the same mother.

A is therefore B's mother's brother, which makes A the maternal uncle of B. So C is correct.

• A) Son: A would be B's mother's son only if B's mother were A's mother, and the statement rules that out.
• B) Father: A is B's mother's sibling, so A is on the mother's side of the family and cannot be B's father.
• D) Brother: A and B are separated by one generation, so they cannot be brothers.

Core concept: blood relations decoded through the mother's family tree. Draw the tree before answering, since reasoning items like this reward a clear diagram. The same skill of tracing family links helps in Mains ethics and family-based case studies.

Trap: students assume B's mother is A's mother, or try to make A B's brother. Map the generations first.