Blood relations – mapping to maternal grandmother: A man said to a woman, "Your brother's only sister is my mother." What is the relation of the woman with the man's maternal grandmother?

Introduction / Context:
We first identify who the woman is to the man and then infer her relation to the man's maternal grandmother.

Given Data / Assumptions:

• "Your brother's only sister is my mother." If the woman's brother has only one sister, and that person is the man's mother, then the woman is that only sister ⇒ the man's mother.

Concept / Approach:
If the woman is the man's mother, her relation to the man's maternal grandmother (the woman's own mother) is simply "daughter."

Step-by-Step Solution:

Verification / Alternative check:
Family tree labels confirm: GM (maternal) → Mother (woman) → Man. Relation asked is Daughter.

Why Other Options Are Wrong:
Mother/sister/niece/granddaughter misplace generations relative to the grandmother.

Common Pitfalls:
Assuming multiple sisters; the statement specifies "only sister."

Final Answer:
Daughter