A man pointing to a photograph says, "The lady in the photograph is my nephew's maternal grandmother."
How is the lady in the photograph related to the man's sister who has no other sister ?

A. Cousin
B. Sister-in-law
C. Mother
D. Mother-in-law
Answer: C . Mother


Clearly, the lady is the grandmother of man's sister's son i.e., the mother of the mother of man's sister's son i.e. the mother of man's sister.
So, the lady is man's mother.