Pointing to a girl in the photograph, Amar said, "Her mother`s brother is the only son of my mother's father." How is the girl`s mother related to Amar ?

A. Mother
B. Sister
C. Aunt
D. Grandmother
E. None of these
Answer: C . Aunt

Justification: Only son of Amar's mother's father -- Amar's maternal uncle.
So, the girl's maternal uncle is Amar's maternal uncle.
Thus, the girl's mother is Amar's aunt.